#entropy zero g/t
Explore tagged Tumblr posts
trollsntrash · 9 months ago
Text
Tumblr media
"So, can I call you Big Boss now?" "Fuck you, Wilson." messing around with gmod animated props and discovered there was a model resizing feature so i made entropy: zero g/t out of boredom
clone cop's NOT amused LMFAOOO
5 notes · View notes
sunnydaleherald · 5 months ago
Text
The Sunnydale Herald Newsletter, Wednesday, September 18-Thursday, September 19
Master: You're dead! Buffy: I may be dead, but I'm still pretty. Which is more than I can say for you.
~~Prophecy Girl~~
[Drabbles & Short Fiction]
Tumblr media
Nothing's The Same (Buffy, PG) by badly_knitted
bufy a girl (Buffy/Spike, M) by lottiecrabie
Tumblr media
A Tale of Two Slayers (Buffy/Kendra, E) by Ann_Douglas
Convincing (Buffy/Giles, T) by simple_nothings
[Chaptered Fiction]
Tumblr media
Erotic Entertainment, Chapter 4 (Multi, E) by TheInfiniteDoctor
Cat Scratch Fever, Chapter 2 (Buffy/Cordelia/Oz, E) by KNZ1
My (love) Kill, Chapter 1 (Buffy/Spike, G) by scared_worm
Tumblr media
Love Lives Here, Chapter 100 (Buffy/Spike, NC-17) by Passion4Spike
Forty-eight days in LA, Chapter 7 (Buffy/Spike, NC-17) by Blissymbolics
Mysterious Destinies, Chapter 10 (Buffy/Spike, NC-17) by EnchantedWillow
Lost in Desolation, Chapter 9 (Buffy/Spike, NC-17) by Melme1325
Tumblr media
A Nice Surprise, Chapter 1 (Crossover with Riptide, FR15) by calikocat
Meanwhile, back on the farm..., Chapter 6 (Multiple crossings, FR13) by hysteriumredux
Seeing Clearly, Chapter 200 (Multiple crossings, FR13) by JoeB
Tumblr media
Perception, Chapter 4 (Buffy/Spike, G) by flootzavut
Champion of War, Chapter 3 (Buffy/Spike, NC-17) by Desicat
To All We Guard, Chapter 25 (Buffy/Spike, NC-17) by simmony
Waiting for You, Chapter 21 (Buffy/Spike, NC-17) by honeygirl1885
A Sword in the Man, Chapter 4 (Buffy/Spike, PG-13) by Desicat
[Images, Audio & Video]
Tumblr media
Artwork:The Slayer's pet by JSBirsa
Tumblr media
Manip:moodboard: buffy summers by courtillyy
Manip:Collage #172 by thedecadentraven
Gifset:Buffy Meme: [1/8 Episodes] 6x07 Once More With Feeling by lovebvffys
Gifset:7x15 | “Get It Done” by clarkgriffon
Gifset:6x18 "Entropy" by peeta-mellark
Gifset:Timestamp Roulette 3x03 | Faith, Hope, & Trick by clarkgriffon
Gifset:3.04 | Beauty and the Beasts by bangelgifs
Gifset:Mercedes McNab as HARMONY KENDALL 🦄 by whatisyourchildhoodtrauma
Tumblr media
Video: Buffy Best Comebacks // Buffy The Vampire Slayer Funniest Moments by Hollistic Witch
Video: Buffy and Faith - Empty by juliaroxs241
[Reviews & Recaps]
Tumblr media
Big Bad Powerful She-Witches | Buffy the Vampire Slayer 7x9 "Never Leave Me" | Normies Reaction! by The Normies
Buffy the Vampire Slayer 4x11 & 4x12 REACTION | "Doomed" & "A New Man" by The Horror Bandwagon
Buffy the Vampire Slayer REACTION | Season 7, Episode 8: Sleeper by JayPeaKay
*BETTER THAN MCDONALD'S?!* Buffy the Vampire Slayer S6 Ep 12 "Double Meat Palace" Reaction FIRST by Nick Reacts
First Date: Buffy 7x14 Reaction by Dakara
[Fandom Discussions]
Tumblr media
[Something Blue with zero context] by mybloodyvampire
[Headcanon- Dru has a lot of things] by voices-not-echoes
Tumblr media
Question relating to Season 7 by multiple authors
I just watched s6e19 for the first time… by multiple authors
I do like this moment of sincerity by multiple authors
Poll - Would you rather scenario regarding Giles in season 7 by multiple authors
The man in the middle by multiple authors
How has your perspective on the show changed as you get older? by multiple authors
What's on your Drusilla/Spike playlist? by multiple authors
Why is "Anne" such an disliked episode? by multiple authors
What are your best Buffy trivia questions? by multiple authors
How much time passes between 'The Body' and 'The Gift'? by multiple authors
Jasmine's best exploits/power statements? by multiple authors
Top 2 favorite episodes... by multiple authors
I finished the show 20 years ago, and I’m only on season 1 of my rewatch, but I have thoughts about Cordelia and Angel by multiple authors
Buffy and Anya by multiple authors
Response to criticism over Buffy’s perceived hardness in S:7 by multiple authors
What did Faith and Willow talk about on their car ride back from Los Angeles? by multiple authors
Just finished watching Angel for the first time ever-VENT by multiple authors
It always seemed to me that Willow's arc was setting up to stall before Smashed and Wrecked by multiple authors
I Robot, You Jane appreciation thread by multiple authors
Buffy The Vampire Slayer is one of the most iconic shows ever produced but which season was THE season and why ? by multiple authors
Submit a link to be included in the newsletter!
Join the editor team :)
5 notes · View notes
camuslvr · 20 days ago
Text
You ever think about how the universe is already dead? Not in the poetic sense, not in some grand metaphor about human decay—literally dead. Just hasn’t finished twitching yet. See, entropy doesn’t stop. It doesn’t slow down. Everything that burns cools, everything that moves stops, and one day, every star that ever lit up the void is gonna gutter out like a cigarette in an ashtray. That’s heat death. The final silence. The end of everything.
And it’s not some distant, hypothetical horror. It’s happening right now. You feel it in your bones, in the way your body breaks down a little more every day. That ache in your joints, the way your memories slip through your fingers like sand—that’s entropy, man. That’s the same law that’s gonna tear the universe apart, working its way through you on a smaller scale. Every living thing is just a temporary structure, an arrangement of matter pretending it has permanence.
Heat death isn’t just an end. It’s the end. The final state of everything. People think of death as something with edges, something with borders—the moment your heart stops, the second the light leaves your eyes. But that’s a small death. That’s just biological failure. Heat death is bigger. More absolute. It’s not just the death of living things, or planets, or stars. It’s the death of difference.
Entropy, mathematically speaking, is a measure of disorder—more precisely, it’s the number of microstates that a system can occupy.
S = k_B ln(Ω)
Where S is entropy, k_B is Boltzmann’s constant (1.38 × 10⁻²³ joules per kelvin), and Ω is the number of possible microscopic configurations of a system. That’s the math of inevitability, right there. Because as a closed system progresses, it moves toward higher Ω, higher disorder. More ways to arrange itself. That’s why you can’t unburn a fire, why you can’t unscramble an egg—because those higher entropy states vastly outnumber the lower ones. The universe doesn’t ‘prefer’ chaos, it just follows probability. And the probability of the entire universe spontaneously reorganizing itself into something structured again? Functionally zero.
Now, extend that to a cosmic scale. The universe right now is a nonequilibrium system—it’s full of energy gradients. Hot stars, cold space. Galaxies spinning in the vast dark. But that won’t last. Every time a star burns, it’s not just producing heat and light. It’s spreading energy out, making it less usable. That’s what free energy is—energy that can still do work. Once energy spreads out evenly, once everything is the same temperature, there’s no gradient left. No work. No structure.
ΔG = ΔH - TΔS
Where G is free energy, H is enthalpy (total energy), T is temperature, and S is entropy. You see that negative sign? That’s the kicker. As entropy (S) increases, the ability to do work decreases. The universe isn’t just dying—it’s fading. Every action, every reaction, is just one more step toward equilibrium, which is just another way of saying ‘universal heat death.’
It’s not an explosion. It’s not fire or collapse. It’s just everything slowing down. Cooling. Spreading out. Until every last subatomic interaction ceases, not because something stopped it, but because there’s simply nothing left to move. No energy left to transfer. No gradients. No contrast.
And here’s the part that’ll keep you up at night: It’s irreversible. The moment the universe started, the moment that first asymmetry emerged, this was always the final destination. You can’t stop it. You can’t fight it. You can’t invent some last-minute technological miracle to turn back the thermodynamic clock. There’s no equation that undoes entropy. The only way to reset the system would be to violate the laws of physics themselves.
So when the last remnants of existence flicker out—when the black holes evaporate, when the last protons decay, when even fundamental particles stretch into meaningless diffusion—that’s it. No afterimage. No memory. Just perfect, absolute nothing.
Because everything, everything that’s ever happened, has only happened because of contrast. Hot and cold. Light and dark. Order and chaos. Without that, without imbalance, nothing can exist. No movement. No thoughts. No matter shifting from one state to another. Just a uniform, static void stretched so thin that reality itself stops functioning. You can’t even call it blackness, because blackness implies the possibility of light. You can’t even call it silence, because silence needs something to compare itself to. Heat death is worse than destruction. It’s the absence of destruction. No fire, no explosions, no final moment. Just an infinite suffocation.
No memory of what came before. No last observer to bear witness. No evidence that there was ever such a thing as ‘something.’ Just an infinite, frozen void stretching in all directions, unchanging, unbroken.
And yet, here we are. Waking up. Pouring coffee. Loving people. Building things. We pretend we matter, because the alternative is realizing we were ghosts the whole time—just flickers of heat burning themselves out in a universe that’s already gone cold.
Maybe that’s all we are. Just sparks flying off a dying flame, burning bright for a second before the darkness swallows us whole.
1 note · View note
stucky-ficrecs · 5 years ago
Text
Completed WIPs, June 2020
The Color Of Blood by MonsieurBlueSky (MyChemicalRachel) (T, 9K)
8:31pm by justforme23 (T, 1775)
Otherkind by MizDiablo (E, 65K)
Toothpaste Kisses by buckybees (T, 19K)
Try Me On For Size by fandomfluffandfuck (E, 7K)
where else would we go by kocuria (G, 1433)
A Higher Epsilon by deadto27 (E, 91K)
Red Carpet Rescue Mission by darter_blue (E, 10K)
Encouragement and Persuasion by orphan_account (NR, 36K)
The Discovery by fandomfluffandfuck (E, 5K)
Siberia by CC99trialanderrorgirl (E, 10K)
A Study In Steve Rogers' Stupidity by TheGameIsOver (T, 8K)
He Wears It Well by roe87 (E, 15K)
Nothing colder than being alone by lalalalalahahahahaha (M, 4K)
Heavy Lies the Head by inflomora, odetteandodile (M, 60K)
The Safer Course by seapigeon (M, 8K)
Broken memories by mcuwhore (G, 26K)
Very, Very Easy To Be True by Whendoestheshipsail (AO3 login required) (E, 57K)
Paradise Lost (& Found) by JJK (M, 121K)
Latte Art and Slow Dancing in the Dark by deadonarrival for The Twitter Collaborative (E, 90K)
“Hey, Sarge, you got a dame?” by rox_fanfics (T, 3K)
Out Of Order by Marvel_Mania (E, 19K)
Bucky Makes Cheesecake for Clint's Birthday Dinner by E_Greer (M, 8K)
way far beyond by squirmingbubbles (T, 7K)
Third one's the charmed by NatyCeleste (E, 12K)
When The World Was At War (we just kept dancing) by PeachyKeener (E, 41K)
Renegades by crinklefries (M, 142K)
Phase One: MechAvengers Assemble by DarkFairytale (T, 51K)
Podfic for "Dinner for Two" by Dira Sudis by MsPooslie for Dira Sudis (dsudis), hpismyhomeboy (E, 22)
Take Me Home by fandomfluffandfuck (NR, 5K)
cradling the flame by astudyinsolitude for ZepysGirl (E, 17K)
Brooklyn Syndrome by lordelannette (E, 158K)
They Were Zoomates!!! by Written_prose_things (G, 4K)
college 101 by mareviils (E, 14K)
Under the Table and Dreaming by Daretodream66 (M, 76K)
So. You want to know more about the A/B/O universe. by moonythejedi394 (M, 13K)
Corrupted by nerdyrose24 (T, 3K)
The Comeback Kid by grimeysociety (E, 169K)
Latitude Zero by Madara_Nycteris (E, 27K)
why would i shake your hand (when i could shake your bed)? by mediocre_fanfics (NR, 23K)
in the ruins of our worlds by made_of_sunshine (T, 56K)
Old Friends, New Problems by BFab (NR, 14K)
A Perfect Prescription by thewaythatwerust (E, 45K)
I Call Out Your Name, It Feels Like a Song I Know So Well by breatheforeverypart (M, 21K)
two gentlemen of brooklyn by rooonil_waazlib (E, 8K)
Baby Seasons Change But People Don't by fandomfluffandfuck (NR, 6K)
put you on something new by howdoyousleep, the1918 (E, 14K)
Raging War Within by softboibarnes (E, 124K)
Any Day We Can Wash Out To Sea by ashdeanmanns (NR, 26K)
entropy by truehumandisaster (NR, 4K)
Starting Over by Annaelle (T, 50K)
Everybody's a Dreamer by powerfulowl (StuckyFlangst) (E, 13K)
Quality Wood by cloudycelebrations (G, 600)
14 notes · View notes
nelsonbeauchejason · 2 years ago
Text
youtube
youtube
Tumblr media
youtube
5x5 == *Y.ank E&/|&3\B
RSC:BeCCa
U🏏🫧🚽
K🪠🚾🚿
RA(C++);
]T🎧@[:😁 ‘AR$U$
youtube
NA:[R]
🤩🎶🎵
🎧🎼👩‍🎤
youtube
E 👨‍🎤[🎻]🤔 <- 💭
R {^.*}’a.$.c = 📍
G QL ALF:🪕 == 🍁
O I🆚🎹; Tu -> Du%.dd
Tumblr media
W AS H8F8CHK ? M*
🤩’DA +e R—i $V.etI &V3 =🧖v⚠️.@💫6^2Z
🌊[
Tumblr media
🥣<Ti~T@-MLe3^🍰>@
[🍼:$&ap&U QA
$BUN.exe -🍽️.UB>DB4.$ -io -UX
😎@🌟] M.O. {🥄}P🆚 R:Q
C i =📍<=:N.UM<—]nI8—P
Tumblr media
*^-[~]:
H.EX E(8);L<D🥢’X
>e%Pi’
>$ 😁.exe -opt66 -view -7D81
$😑.FHÆ(🎠🧲🐪); AuTO:-🪫.CMD
BGr*.* &! ‘YEll’&”OW”..
6]x9[:96—H2]O, (SPlinDA); {⛲️, s-infinitive}.(…
..
UTIL(Prior S; a cogito; sm-3); [gerund, 🌄].. …)
.1😒 (48✒️3P8 = H8.NuLL) ; —I <=> 🦻’ha’
.2😛’h😤H <-8🖋️FxEh.00
.E🎯.🧝‍♀️.S🧝4
P☕️R🗣️O🔊DuC🔉T = .^. S‘📣
M’🧭 & “W [‘🔈]
I = S[4.MEM]&E..
💭 <=> [.@*]
@ ‘I’ <PHD@:8🏧8:-er:> “O “ :: @A+1 :🔻:0
Tumblr media
R/3:<<=:DAP
O = AD
A !== [#&] T[$AvP] @🅿️00P; mDNA
Z a:🍯
a 🦡:z
NaH:0🐝
2{np(🥣);
P(🍼|^:🦧:-SM&P EaveLR/2)
<🥄F^L>iK.3X>E—
:$🍽️,TYPES E%MAD.di :$: T$eve-N$T0$
🥢—i :💭:
O [🍼Yi—N m, I] :🤔:
U == Particular(👁️|//😳🤚🔙; 🦀)
Q⚓️ = {🐚🥡🧃} == QA
BU N AZN ZzZ BOT-tOm HE -> 3N.EM AP
T 🥛; zero-sum STAigiN’ TEST MA@ FR MA
N 🌌.T4ReLé AS C^E’M:EA 😮 A.EA 😮
Sound; Induction D0 <- Beg[🧊]
Abducting-DeDuction 🍷 <- W__$
UNSouN’: Epistemological D1 M__%
OrTHoGoNai :. PREmi$e. I°E0 CON:P2,P1
youtube
pReMi$e PMP;🅿️ E G^Tu à {|🪨💭🥡|};
😖!🧴:🚖
🅿️ = Quench(Â^BoMB<-8|PrioR);
(
MeTHod A = DeB[8]^(ORa) &H.it(t*h)
T-I =! C^2 cos [(FIFO), (LIFO)]
E-D = <FTE> /‘J__1@YAh/OO.CoM’
E&D-A:8:=:8N-BEck i.e. EX’LuSi = ”3,” e.g.)
)&🅿️v👦
Tumblr media
P🥡&🦀S;4P https://youtu.be/9p_U_o1pMKo FY
TY
TU
^PiPe & @Foe,
#Do&e-3^S’X
#XoDx && YoDy FR E!=[VALuE]
Tumblr media
TR:ERR; 5x5 = {me,myself & ‘i’}
youtube
😹EAM is RoRfnRIM(🍯);
youtube
#MSG; B*R*B.8.1.3.69-Tu-🪫 && 📢
UNK KNOWN
🏳️‍🌈
KNOWN UNK
🦄
ENTROPY 🏹 SIGINT ☔️
G🏌️‍♀️a🩲m👙B🤿Lé A🩱M 🪟PyoX *~i:.
.:~i[*🧻-P|TuR’N domain’s,
N-geNSUffI T.fprint] ::
x(RAND🕊️)🏝️.MSD ? M ! SUBJECT .?.
*^*^*^*^*
LIFE ALERT Flee THen Fight
*v*v*v*v%[fn(dx); b8KoVj^i
B🖤i⏮️L🧻
D��📥💝☑️📥📦
I📫🧃🗃️📭🥊🚃
VeKTOR 📥L,📦L,🎁u,✅N.N
O📫Pro📤P🗳️er 📮T🥡, i🍱e
GoS4, e.g.
RECOMMEND THE REST OF OUR FAMILY AND THEN GO LIVE WITH YOUR EYES TODAY AND GET YOUR OWN MONEY 💰
youtube
M🪟oY🌬️u🍃N🪟R🎋oY🏡g🎄Bi🪟V📴 BuF -ARDuOuS$ &_OvR ‘_BoT@
U->
<-D
F :: 💋
B;🎯
L-is-👉
Tumblr media
R $į 👉H.ike—K.i🐼👉U🎩👉M☕️str🔢
👉I🧂👉N🛹👉T🅿️remise2
Undivided M’D; medium
Tumblr media
[THOT]
{RAPE}
J(;$)K$-/in//var/i//a/nt
$>&Predicted @v@
Tu fn dmDB rn Q s;tiL(B&)e[&L] e.g.
I A M B a d B o i {i,s,g,&u; n&m:@C&} C.HuE
Tumblr media
EGO-ToKen
Lose-Lose &”UH-LO$,’3
THis.is.DeaTH.🧬
S🫣P🕵️‍♂️T🕵️‍♂️Ca🕵️‍♀️s👀t
youtube
Strategy Process ⚧️ 4pL(♠️)orM@
🏦>💶
🏧<💷
💴>💸
💚⏲️ == 💓👔💞 SUCCESS = ⌛️
💖🔐💞👩‍💻🏴‍☠️
🧑‍💻x👨‍💻
:🕳️:
“To have someone understand your mind is a different kind of intimacy.”
— Unknown
4K notes · View notes
arxt1 · 5 years ago
Text
Gravitational domain wall in two-dimensional dilaton gravity. (arXiv:2006.07962v1 [hep-th])
We study a special two-dimensional dilaton gravity with Lagrangian $\mathcal{L}=\frac{1}{2}\sqrt{-g}(\phi R+W(\phi))$ where $W(\phi)={\rm sech}^2\phi$. This theory describes two-dimensional spacetimes that are asymptotically flat. Very interestingly, it has an exact solution for the metric, ${\rm d} s^2=-(\tanh x){\rm d} t^2+1/(\tanh x)\, {\rm d} x^2$, which presents an event horizon but no singularity. Because of the kink profile for the metric components appearing in this solution, we refer to it as gravitational domain wall with the wall simply being the event horizon and separating two asymptotically Minkowskian spacetimes. The global causal structure for such an object is studied via coordinate extension and the thermodynamical quantities are computed. While the gravitational domain wall has non-zero temperature $1/4\pi$, its energy and entropy are vanishing.
from gr-qc updates on arXiv.org https://ift.tt/3hwHU5L
0 notes
doodlyaim · 7 years ago
Text
n e g a t i v i t y   w e e k
Huy ano puro negativity na-aabsorb ko ngayon linggo. Hindi nakakatulong sa totoo lang, sobrang affected ako ng negativity ng surroundings ko. Entropy is really greater than zero. My patience is sagad na bes, all i did every time someone is annoying me is to shout at them coz they are really getting on my nerve. An exception to my madness is the only person who motivate me na kaya ko to, thank you girl! The rest are annoying me. Ang weird maybe dahil rin sa hormones kaya ganito ako. Like i find everything around me maddening to the highest level. Back to old me again? :-(
Im ranting on tumblr kasi my Twitter acct is inactive and people will gossip and judge you and act like they care but the truth is they dont really give a fuck. 
Sorry, i just need to get this thought out of my head. And this is not good coz im putting a lot of negativity here. 😭😭
0 notes
subkulturrecords-blog · 7 years ago
Video
musicians with guns - overstepping artifacts from ricardo montalban on Vimeo.
Musicians With Guns - Overstepping Artifacts LP (drone/ambient/eperimental/LoFi music) ---> entropy-records.com/release3032.htm
*** New fractal video for Art Zero label here : vimeo.com/85096694 ***
> / °°000 - #CLS > / °°010 - #LOAD /mwg/protocol/crawling through the amazing box -r -p -s -n > / °°022 - #RUN -- > / °°143 - #ERR [00054d64-ba6c5411] ; "nonlinear overlapping function" > / °°285 - #LIST [4016457fa-6552b31c] > / °°299 - #DEBUG [23d3c447-9ff4c812] > / °°356 - #COORD [????????-????????] > / °°387 - #TRACE [535b8c47-88f5a7bb] ; "analytical distance estimator" > / °°408 - #ERR [012d2556-9a9b1445] ; "overstepping artifacts" > / °°437 - #LOSTINTIMEANDSPACE [8342dc41-e4a22f1b] > / °°446 - #MOFRACT [7271dd5c2 - a948b8d4] ; "half octahedral planes" > / °°489 - #ROTATE [61d5f4aa-62b49c10] ; "helispiral rotation" > / °°524 - #TRAPPED [33a49ee2-bb6462c7] > / °°551 - #ZOOM [+inf/-inf -g -s -t] > / °°637 - #ERR [e682b6d4-fe945aa0] ; "lost in a different coordinate system" > / °°793 - #NOEND /mwg/cometa -i
0 notes
sikoko · 7 years ago
Text
Don't Fear The Reaper
I've mostly stopped development on my honeypot. Instead, I'm just watching the logs for any unusual behavior. About 3 weeks ago, I noticed something odd. The number of SYN-scans against 23/tcp took a dramatic uptick. The ports under attack looks similar to the Mirai botnet, so this appeared to be yet-another Mirai variant. I've been profiling different types of botnets, and I call this one 'Botnet[E]'. (Botnet[A] refers to the network library used by Mirai.) Except... My honeypot records a lot of detail about the packet header. One of the things that I began recording last month is the TCP sequence number. And with these attacks, I kept seeing the same sequence numbers over and over. In this case, the TCP sequence number (a 4-byte value) was the exact same as the IP target address (a 4-byte value). This becomes a very distinct value for identifying this particular scanning bot. And based on the number of IP addresses during the scanning, this is a huge botnet.
Sequencing
The TCP header contains two fields for counters. There's the sequence number and the acknowledgment number. These two fields work together during the TCP 3-way handshake and data transfer:
Handshake step 1: SYN. During the initial connection, the client sends a SYN packet to the server. The SYN packet sets the initial sequence number. This could be literally any 4-byte value -- it just needs to be set. The ACK number is ignored and usually zeros.
Handshake step 2: SYN-ACK. The server responds with a SYN-ACK. The server sets it's own initial sequence number, and responds with the client's sequence number as the acknowledgment number. This tells the client that the server has synchronized with the client's counter.
Handshake step 3: ACK. The client responds with an ACK. The sequence number should not change, and the server's sequence number becomes the acknowledgment number. This tells the server that the client has synchronized with the server's counter.
Data transfers. After the handshake, both sides start exchanging data. The server's sequence number increases by one byte for every byte of data that the server sends to the client. And the client's sequence number increases by one byte for every byte of data that the client sends to the server. The corresponding ACK packets tell each side how much data has been received and whether to resend data that got lost.
Different systems use different methods to initialize these TCP sequence numbers:
Old operating systems. Old systems would initialize it based on something like the current time, current uptime, or just use an incremental counter. The time-based initializers were fun, because you could tell the system's time or how long the computer had been up since the last reboot just by looking at the initial sequence number. However, if an attacker can guess what the sequence number will be, then they could hijack the TCP connection. For this reason, most systems have moved away from time-based initial values. Today, time-based initial values are still the case with some embedded devices.
Modern operating systems. Most of today's computers use an effectively random value to defeat information leakage.
Scanners. Tools like masscan and zmap are capable of scanning the entire Internet in under an hour. They can sling out a huge number of packets. Of course, they don't want to store every outgoing packet sequence number. Instead, they just want to send out SYN packets and see what (if anything) responds. These tools initialize the sequence number with a pre-determined value. For example, the initial sequence could be the 1st four bytes of hash(entropy XOR target IP address XOR port number). This makes the sequence numbers look random, but the scanner can tell when a valid response is received. (This stops jerks from flooding the scanner with fake SYN-ACK responses. Since you don't know the sequence number, the fake SYN-ACK is ignored.)
Botnets. Different botnets use different initial sequence values. One botnet that I see often uses an initial sequence number of 0x00000000. Another botnet uses a two-byte value, leaving the first two bytes zero. For example, seq=00000e44 and seq=0000441a. And a different botnet leaves the last two bytes zero: seq=0a4d0000 and seq=467e0000. In these cases, it's not just that it's a botnet. I can tell the botnet family based on the sequence number format.
And that brings us back to this new botnet. It initializes the TCP sequence number with the target's IP address. For example, if the SYN packet is sent from 201.52.93.90 to 182.231.151.141, then the initial SYN packet's sequence number will be 0xb6e7978d (that's 182.231.151.141 written in hex, or 3,068,630,925 in decimal). This is actually kind of brilliant. Each bot slings out packets and doesn't store any information. When a response comes back, the botnet can identify the sender by the sequence number. Moreover, if the response sequence number doesn't come from the sender's network address, then they can use this information to partially map out network addresses. (Although more likely, they just use it to check if the SYN-ACK is valid, or ignore it altogether and just use the SYN-ACK packet's sender address.) Of course, since I know the sequence number, I can be a jerk and send back SYN-ACK responses for arbitrary addresses. I just need to wait until my honeypot receives one of these scans. At that point, I know the IP address of an infected IoT devices. Then I can start sending back fake packets with fake IP addresses but valid sequence numbers in the ACK field. This will make the botnet think that lots of systems are vulnerable, even when they aren't. Each node in the botnet may end up spending a lot of time attacking ghosts. This either slows down the scan as they attack nothing, or fills the attack queue with garbage. And yes, I've been doing this for a week. Here's my script:
#!/bin/bash # Attack back ip2dec () { local a b c d ip=$@ IFS=. read -r a b c d <<< "$ip" printf '%d\n' "$((a * 256 ** 3 + b * 256 ** 2 + c * 256 + d))" } tail -f /var/log/honeypot.log | grep --line-buffered seq=ip.src | sed -u -e 's@^.*honeypot: @@' -e 's@\[@ @g' -e 's@\]@ @g' -e 's@/tcp@@g' | # My logs include source address, source port, destination address, and destination port # The source is the botnet. while read src sport junk dst dport junk ; do # Send 10 fake responses loop=0; while [ $loop -lt 10 ] ; do # Don't use the real destination; select one at random. # Or I could loop over specific addresses I want the botnet to attack. dst="$((RANDOM%6)).$((RANDOM%6)).$((RANDOM%6)).$((RANDOM%6))" # Derive the sequence and acknowledgment numbers from the addresses. seq=$(ip2dec "$src") ack=$(ip2dec "$dst") # Get the date for logging date=$(date +"%Y-%m-%d %H:%M:%S %Z") echo -n "$date " # SYN goes from src to dst #echo "SYN from $src:$sport[$ack] to $dst:$dport" # SYN-ACK goes from dst to src echo "SYN-ACK from $dst:$dport[$seq] to $src:$sport[$ack]" # use hping3 to send the fake packet hping3 -q -i 1u -c 1 -a "$dst" -L "$ack" -M "$seq" -t 242 -s "$dport" -p "$sport" -S -A "$src" > /dev/null 2>&1 ((loop=$loop+1)) done done
My honeypot is currently receiving scans from this botnet about 1-3 times per minute. And it is rare to see the same infected IP address twice. Nearly all are scans for 23/tcp. There is a small percent of scans for 22/tcp, 2323/tcp, and other ports.
Comparing Results
Good science means that results can be repeated, and the same results can be determined using different means. I've been communicating with Troy Mursch from Bad Packets. He runs a honeypot but doesn't use the same tools as me. (I wrote my own tools, so I'm very certain that we don't have the same setup.) Every now and then, I'll send him a query like, "Are you seeing any activity from xx.xx.xx.xx?" or he'll ask if I just received a flood from yy.yy.yy.yy. (It's really entertaining when the initial response is "no", but a few hours later it changes to "yes -- they just showed up.") Troy and I began comparing notes and findings with regards to packets with this specific fingerprint. We were seeing the same volume of traffic, same types of source hosts, and even the same ports being scanned. (The vast majority of scans were for 23/tcp. A distant second came 22/tcp, then 2323/tcp, and other common IoT ports.) Troy has a write-up of his findings at "EnGenius Routers Found in Reaper Botnet with Distinct Network Fingerprint". Going back through our logs: I had been seeing these scans since mid-September. At least, that's when I started tracking sequence numbers. Troy traced through his logs and found this same profile dating back to early May 2017. We compared the observed source addresses and, amazingly, had very little overlap. That means that this botnet is massive. Something in the "millions of infected hosts" range. We had been working on tracking this botnet for about a week, when the news broke. There's a new big botnet in town. Checkpoint Research calls it "IoTroop", but other security companies are calling it "Reaper" or "IoT_reaper". Like the Mirai botnet, Reaper infects IoT devices. But there's a twist. With Mirai, it just looked for default logins on IoT devices. Reaper also uses a few known exploits to compromise the IoT devices. As Andy Greenberg at Wired described it, "It's the difference between checking for open doors and actively picking locks." As soon as I read the description and the timeframe for when it appeared, I became convinced that Troy and I had been looking at packets from Reaper. It's the same timeframe, same volume, and same types of devices. As botnet infections go, this one is bad because of the sheer size of it. If the owner of this botnet were to use it for a DDoS attack, the results would be enough to take Brian Krebs offline. (And Brian's been able to withstand some really massive DDoS attacks.)
Detecting Reaper
Most of the reports about the Reaper botnet lack details for detecting an infection. The folks over at Radware have a detailed report that lists ports that Reaper scans. However, I'm not able to validate their findings. For example, they say:
The first wave consists of SYN scans on TCP ports in the following order: 20480, 20736, 36895, 37151, 22528, 16671, 14340, 20992, 4135, 64288, 45090, 21248, 21504, 31775, 39455, 47115 and 42254.
I'm just not seeing this in my logs. For example, in the last five days, my honeypot has seen five (5) scans against 20480/tcp. All five of those had the TCP SYN sequence set to the destination IP address. In contrast, during that same timeframe my logs identified 4,212 scans from Reaper -- and most were against 23/tcp. Perhaps Radware is talking about how Reaper appears on the infected system, or how Reaper attacks a vulnerable system, and not how it looks as it tries to spread across the Internet. I'm also seeing a much wider range of infected devices that those listed in the other researcher reports. To test devices, I just waited for the IP address to scan me, and then I checked for a publicly accessible web server. For example, I saw a scan from 168.167.177.180 and saw an infected airOS router. (You can tell it's infected because of the code error at the top of the page.) And here's an accessible TripMate Nano that scanned my honeypot: NOTE: It defaults to filling in the username as 'admin'. I didn't type that. The TripMate Nano scan was shortly followed by a D-Link router: For network administrators who want to detect infected hosts from this new botnet: Look for SYN packets where tcp.seq==ip.dst. If you see a match, then the ip.src denotes an infected address. Either the device at that address is infected, or something behind that NAT router is infected. Source: http://ift.tt/2zS84di
0 notes
chemphdblr-blog · 8 years ago
Text
[under construction] first year undergraduate thermodynamics: a simplified glossary, discussion and sign convention summary
V idk about you, but thermodynamics just fucks me up. every. fricking. time. the different sign conventions don’t help either. this a short summary of undergraduate first year thermo; ideally, you would have a textbook and notes to refer to, and this is just a no-nonsense rundown of need-to-knows. this should be nothing more than a springboard for you to review topics and refresh your memory. THIS IS BY NO MEANS A COMPREHENSIVE LIST.
Glossary (will be redefined within equations but important to know&understand these at the start) Δ change; the “big version” of d derivative U (sometimes E) : internal energy.  Q: heat, a form of energy W: work, a form of energy H : enthalpy; the total heat of the system. It is different from Q in that it accounts for any heat lost as work in a system S: entropy. generally we say it is the “disorder”/randomness  G: Gibbs free energy H: helmholtz free energy
Equations (we will go over these individually, but I find it convenient to have them listed at the start so we know what we’re going over; plus it gives me a guideline for how I can connect these and talk about them) ΔU =  ΔQ +  ΔW ΔU = mcΔT +  PΔV c.v = ΔH =  ΔU +  Δ(PV) ****differs from PΔV***** (not discussed here, but note H = ΔHproduct - Hreactant as well, when looking for heats of formation, etc) ΔS =  Δq/T F = U - TS G = U - TS + PV ***note on entropy S in statistical mechanics****
the real stuff ΔU =  ΔQ +  ΔW about: the first law of thermodynamics. it’s another form of conservation of energy. It says that the total energy in an isolated system (((link to a page on isolated system))) is constant. theoretically, should you find Q and W, you know the energy of that system! of course this is unrealistic, but the basis of thermodynamics starts here. the equation, but in words: the total energy in this system (assumed isolated) is equal to the heat energy put into (+)  or released from the system (-) PLUS the work energy the system exerted on the system (+) or that the system did (-).  sign convention: depending on your book or course, you may see  ΔU =  ΔQ -  ΔW. i’m not entirely sure why, but for me, keeping things consistent makes snese. so I like  ΔU =  ΔQ +  ΔW, since a positive  ΔQ and  ΔW indicate energy being put into the system by heat and work. If you find the other way easier to understand, please work with that. but keep in mind what your teacher says the test will be like! Is it a state function? Yes
ΔU = mcΔT +  PΔV  about: So, this is the most common form of ΔU I think you’ll see. Note that it for a system of gases only. Other equations of state will exist in other studies, but I don’t think that’s true for very basic thermodynamics. So this equation arises from Q = mc Δ T and W for gases in some sort of changeable volume (like a container with a piston) is  PΔV.    Sign convention: -PΔV  is the normal convention. mc Δ T is the normal convention the equation, but in words: Is it a state function?: It’s just another form of the above, so yes
ΔH =  ΔU +  Δ(PV)  A related concept to internal energy, so I’ll go into it here rather than the second law.  About: This is mostly relevant for gases. In liquids/solids, the ΔU and ΔH are usually quite close because  there tends to be no or very small change in volume for stuff in those states. Gases, however, can expand/depress; and in doing so, the pressure it exerts on the environment or has exerted on it would change. The volume of a gas expanding or depressing will also change in those cases. Ideally, we would have no escape of gas and a system that is isochoric and isobaric. however, for the most part, it’s untrue. the   Δ(PV)  is expanded out into P Δ V + ΔPV.  **IT DETERMINES EXO/ENDOTHERMICITY** the equation, but in words: since most reactions are done in open containers (i.e., not isochoric or isobaric), internal energy is not total energy of system, you must account for any energy lost as work; i.e., gas pushing (pressure) against a container is work; the gas changing volume is work, etc.  Sign convention: None besides the ones associated with ΔU Is it a state function? Yes
ALSO ΔH =  ΔHfinal -  ΔH intiial Hess’s Law (see notes below)
Consider: water boiling in open container. The energy needed for water molecules to escape the surface of the liquid and overcome equilibrium of condensation/evaporation cycle is very high, more than is accounted for in  ΔU; so  ΔH cannot be zero. 
    ΔS =  Δq/T (for a reversible process) and can be written as ΔU <= TΔS - PΔV,  ΔS >  Δq/T for irreversible process about: entropy has to do with the randomness of a system. the tendency of things to equa out and spread apart; i.e., something hot will try to disperse that heat to something less hot; molecules tend to spread away from each other.  Adds some more “rules” about the energy in a system. The entropy of a system will be the same or tend to get bigger.  Important to note that in a reversible process, it’s the above equation
ΔG =  ΔH - T ΔS gibbs free energy is a relationship that describes whether a chemical reaction is predicted to be spontaneous or not A negative  ΔG indicates it is spontaneous inthe forward direction as written. A zero  ΔG indicates equilibrium; i.e., no driving force forwards or backwards it becomes temperature indepedent when  ΔS is a very small value in in either positive or negative direction; this is bcause the product of the temperature and the entropy would be smaller than the enthalpy change
some terms: spontaneity determines if a reaction will occur or not. IT DOES NOT DETERMINE RATE OR EXO/ENDO THERMICITY spontaneous reactions mean that the products are lower in free energy than reactants exo/endothermicity is whether a reaction gives off heat to environment or takes heat from it 
memorization list (once you understand the concepts, this list is what you need to know on a fast basis. I don’t advocate for memorization EVER but if you’re shaky on topics and you have these memorized, you can sometimes reason your way into understanding something)
a (-) ΔU indicates the system lost energy/did work on the environment. something cooled off, or the container expanded 
a (+) ΔU indicates system got energy from the environment (heat put in by a bunsen burner or you squeezed the container)
(-) ΔQ is heat lost from the system to environment
(+) ΔQ is heat gained by the system from the environment
(-) ΔW is work done by the system on the environment
(+) ΔW is work done to the system by the environment
a (-)  ΔH indicates an exothermic reaction; the system released heat. (think of it as the system put out/lost energy as heat)
a (+)  ΔH indicates an endothermic reaction; the system had to take in heat to occur. 
a (-)  ΔS indicates a loss of entropy (more ordered)
a (+)  ΔS indicates an increase in entropy (more chaos)
a (-) ΔG indicates a spontaneous forward reaction, as the equation is written
a (+) ΔG indicates a nonspontaneous forward reaction, although the reverse *may* be
ΔG = 0 indicates equilibrium. 
when ΔH is (+) and ΔS is (+), ΔG could be either (+) or (-) depending on temperature, and is spontaneous at high temperature
when ΔH is (-) and ΔS is (+), ΔG is always (-) and always spontaneous
when ΔH is (-) and ΔS is (-), ΔG could be either (+) or (-)  depending on temperature, and is spontaneous at low temperature
when ΔH is (+) and ΔS is (-), ΔG is always (+), and is never spontaneous 
Discuss later: Hess’s Law (of constant heat summation): the enthalpy change of any reaction is equal to the sum of the enthaly changes of a series of reactions into which the overall reaction may be divided. (bc enthalpy is a statefunction)  ΔH = sum H (bonds broken) - sum H (bonds formed) *** NOT Hfinal - Hinitial****
thermodyanmic potentials and their relationships [x]
0 notes