topic Re: Help with custom vulnerability signature in General Topics

Help with custom vulnerability signature

SDorsey — Tue, 09 Sep 2014 20:53:28 GMT

Can someone provide documentation and insight in regards to creating custom IPS signatures based on the follow scenario?

Consider you have an FTP server. The USER command is vulnerable to buffer overflow. How does one create a custom signature to identify and block this activity?

The buffer and payload the attack sends could have 1000 variations.

Re: Help with custom vulnerability signature

SDorsey — Tue, 09 Sep 2014 21:11:04 GMT

Further info.. if the vulnerability is simple triggered by sending over 20 characters to it...

An attacker could send 100 A's. We could easily build a signature that watches for 100 \x41. But if they sent a payload of 100 \x42 and caused the crash, the custom signature would not match.

Re: Help with custom vulnerability signature

dburns — Tue, 09 Sep 2014 21:23:36 GMT

Go here for Custom Signature help DevCenter

Dominic

Re: Help with custom vulnerability signature

bat — Tue, 09 Sep 2014 21:33:09 GMT

Hi SDorsey

I think such vulnerability should already be covered in the stock signatures in threat database. I searched through threat vault for some of the USER command overflow buffer vulnerabilities and found the following:

Does the threat database not cover the specific vulnerability you are looking for ?

Thanks

Re: Help with custom vulnerability signature

SDorsey — Tue, 09 Sep 2014 22:51:35 GMT

As oppose to being on a specific vulnerability, this is more a general inquire to try to understand how the IDS signatures work. In preparation for the need to create custom ones. And I know for sure that FTP USER overflow list is missing a few.

I created a new thread in DevCenter

General help with custom vulnerability signature