CitySec meetup for Information Security professionals/hoodlums in Oakland/East Bay. Meets last Thursday of every month at Radio Bar unless otherwise specified.
Oakland, CA
Joined February 2011
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HoodSec retweeted
Understanding that every compressor is a machine learning predictor, and vice versa, was the single most important insight I learnt about between 2019 and now.
this is wild — kNN using a gzip-based distance metric outperforms BERT and other neural methods for OOD sentence classification
intuition: 2 texts similar if cat-ing one to the other barely increases gzip size
no training, no tuning, no params — this is the entire algorithm:
![for (x1, _) in test_set:
Cx1 = len(gzip.compress(x1.encode()))
distance_from_x1 = []
for (x2, _) in training_set:
Cx2 = len(gzip.compress(x2. encode())
x1x2 = " ".join([x1, x2])
Cx1x2 = len(gzip.compress(x1x2. encode())
ncd = (Cx1x2 - min(Cx1,Cx2)) / max(Cx1, Cx2)
distance_from_x1.append(ncd)
sorted_idx = np.argsort(np.array(distance_from_x1))
top_k_class = training_set[sorted_idx[:k], 1]
predict_class = max(set(top_k_class), key=top_k_class.count)](https://pbs.twimg.com/media/F05HxqsWwAAHRCI.jpg?name=orig)
ALT for (x1, _) in test_set: Cx1 = len(gzip.compress(x1.encode())) distance_from_x1 = [] for (x2, _) in training_set: Cx2 = len(gzip.compress(x2. encode()) x1x2 = " ".join([x1, x2]) Cx1x2 = len(gzip.compress(x1x2. encode()) ncd = (Cx1x2 - min(Cx1,Cx2)) / max(Cx1, Cx2) distance_from_x1.append(ncd) sorted_idx = np.argsort(np.array(distance_from_x1)) top_k_class = training_set[sorted_idx[:k], 1] predict_class = max(set(top_k_class), key=top_k_class.count)
HoodSec retweeted
In the early 2000s @StephWehner did malware classification using gzip distance. I felt it was a cute trick but didn't take it too seriously, but more than a decade later I still use the trick of concat/compress to measure pairwise similarity of arbitrary data.
HoodSec retweeted
And understanding that a state-of-the-art compressor is our best approximation of an upper bound of Kolmogorov complexity.
HoodSec retweeted
So I just woke up and apparently I inadvertently discovered a zero-day RCE in acme.sh, and caused a Chinese CA to shut down overnight.
Props to the @neilpangxa of acme.sh for the quick fix! github.com/acmesh-official/a…
HoodSec retweeted
So I gave ChatGPT4 this prompt: Implement strstr() using brute force in C++. Be portably efficient. Do no unnecessary work. Keep the implementation short and clear but give priority to efficiency. 1/
HoodSec retweeted
So there's a great Thai restaurant in my neighborhood called Kiin. Yesterday, I searched for their website to order some takeout. Here's the Google result.
HoodSec retweeted
As I’ve said before, no one should be in jail just for using or possessing marijuana.
Today, I’m taking steps to end our failed approach. Allow me to lay them out.
HoodSec retweeted
if true, this thread has scary implications for anyone who contributes to open source privacy software. basically you can be arrested if criminals use it and the authorities can’t figure out who else to arrest.
HoodSec retweeted
This blog entry (by two talented authors) breaks new ground by being the first foray into applying equality saturation to deobfuscation. Definitely give it a look if that overlaps with your interests!
Improving MBA Deobfuscation using Equality Saturation by @fvrmatteo and @mr_phrazer.
secret.club/2022/08/08/eqsat…
HoodSec retweeted
Oh man, I think we have a winner for best conference presentation title
#HITB2022SIN E’rybody Gettin’ TIPC: Demystifying Remote Linux Kernel Exploitation - Sam Page - conference.hitb.org/hitbsecc…
HoodSec retweeted
Chrome Android and Windows 0day RCE SBX github.com/emredavut/Chrome-… (The one used at blog.google/threat-analysis-…)
HoodSec retweeted
Today is the 25th anniversary of the first time I ever reverse engineered a piece of software. It's been gratifying and rewarding, but I hope to retire from public life before it's time to celebrate the 30th.
HoodSec retweeted
We're planning to try and reboot Hoodsec this month!
Same time, same place - 8pm on the last Thursday (the 30th) Radio bar Oakland
If you want to hang please be vaccinated, and willing to discretely show proof myvaccinerecord.cdph.ca.gov/