The DMZ

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11:03 AM

I think you're confused about msfvenom
You're basically just obfuscating the payload
If the system is not vulnerable, then obfuscation does not help
Try to learn the principles behind the tools before blindly typing all kinds of commands

obfuscation tries to bypass scanners (AVs for example) that use a certain signature
AVs nowadays are quite *smart* as they also do heuristic scanning

if this is for learning purposes, then it's best to do this on known vulnerable/unpatched systems

HamZa

11:34 AM

[Crypto Q] I found an algorithm for generating unique links
it goes like this: md5(time + file_name + secret)
since the secret is at the end, we can't use hash length extension attacks
it seems to me that this algorithm is not "optimal", but i don't know why.
One thing that comes to mind is the fact that an attacker can generate a link, he's in control of the file_name, and theoretically should also know the time, which means that he can perform an offline bruteforce
I've looked into chosen prefix collisions but it does not seem appliable

my crypto knowledge is kind of limited :P

I think the only "defensive" measure here is the "secret", maybe that's the weakness if i follow my instincts

2 hours later…

forest

1:18 PM

Obfuscation in metasploit and such are not designed to evade AV.

SEJPM

1:39 PM

@HamZa the standard reason this isn't used is because it allows for collisions

so if you find a collision for md5(time + file_name) then this can be extended to md5(time + file_name + secret)

win.tue.nl/hashclash/EC07v2.0.pdf

^ this paper talks about given P and P' finding S and S' such that md5(P||S)==md5(P'||S')

so if you know the time / can predict the time

you can find filenames which yield a collision

and thus making the result no longer "unique"

at the cost of about 2^50 MD5 evaluations

which is about 60k USD on-demand on AWS EC2 and about 25k USD using spot instances

2 hours later…

Arminius

3:50 PM

Q: Finding owner of a Wi-Fi network name that may be a threat

I moved into my new home three years ago. All pre-wiring had been installed during the build. The day of move in there was a security company installing the security system which included outside cameras and inside panel systems. At that time I gave the installer general personal information (W...