Need Assistance with Custom Signature for Shamoon

[dgilliam]

We are alerting on Shamoon on our IDS systems, but we want to write a custom signature for the PANs.  Shamoon has two signatures for snort:

alert tcp $HOME_NET any -> any $HTTP_PORTS (msg:"MALWARE-CNC Win.Trojan.DistTrack command and control traffic"; flow:to_server,established; content:"/ajax_modal/modal/data.asp"; nocase; http_uri; content:"&state="; distance:0; nocase; http_uri; metadata:policy balanced-ips drop, policy security-ips drop, service http;reference:url,kc.mcafee.com/resources/sites/MCAFEE/content/live/PRODUCT_DOCUMENTATION/23000/PD23936/en_US/McAfee_Labs_Threat_Advisory-W32-DistTrack.pdf; classtype:trojan-activity; sid:23893; rev:4; )

alert tcp $HOME_NET any -> any $HTTP_PORTS (msg:"BLACKLIST User-Agent known malicious user agent - you"; flow:to_server,established; content:"User-Agent|3A| you|0D 0A|"; fast_pattern:only; http_header; metadata:impact_flag red, policy balanced-ips drop, policy security-ips drop, service http; reference:url,kc.mcafee.com/resources/sites/MCAFEE/content/live/PRODUCT_DOCUMENTATION/23000/PD23936/en_US/McAfee_Labs_Threat_Advisory-W32-DistTrack.pdf; classtype:trojan-activity; sid:23903; rev:2; )

I am trying to figure a way to take these and turn it to a custom signature on the PANs but seem not to be able to find the appropriate documentation to block outbound web traffic that would match the signature.

Any suggestions would be very helpful.

David

[tettema]

Hi David,

I would suggest the following:

Signature 1: Match "/ajax_modal/modal/data.asp" in http-req-uri-path, and "&state=" in http-req-params

Signature 2: Match "User-Agent\x3A\x you \x0D 0A\x" in http-req-headers.