Rule History

SID: 2034358 • Source: et/open

Versions (4)

Version DetailsCurrent

Rev: 1 • Nov 8, 2021, 12:00 PM

Message:

ET MALWARE Cobalt Strike Activity (GET)

Rule:

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Cobalt Strike Activity (GET)"; flow:established,to_server; http.method; content:"GET"; http.uri; content:"/oscp/"; startswith; fast_pattern; pcre:"/^[a-z]{256}$/R"; http.header_names; content:"|0d 0a|Accept|0d 0a|Host|0d 0a|User-Agent|0d 0a|Connection|0d 0a|Cache-Control|0d 0a 0d 0a|"; bsize:57; reference:url,www.cert.ssi.gouv.fr/cti/CERTFR-2021-CTI-009; reference:md5,f790bea81673806479e30337629fa605; classtype:trojan-activity; sid:2034358; rev:1; metadata:attack_target Client_Endpoint, created_at 2021_11_08, deployment Perimeter, deployment SSLDecrypt, malware_family Cobalt_Strike, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_11_08;)

Created:

Nov 8, 2021, 12:00 PM

Updated:

Nov 8, 2021, 12:00 PM

DB Created:

Sep 21, 2024, 3:00 AM

DB Updated:

Sep 8, 2025, 9:34 PM

Filename:

rules/emerging-malware.rules