Cobalt Strike Named Pipes

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Description

The following analytic detects the use of default or publicly known named pipes associated with Cobalt Strike. It leverages Sysmon EventID 17 and 18 to identify specific named pipes commonly used by Cobalt Strike's Artifact Kit and Malleable C2 Profiles. This activity is significant because Cobalt Strike is a popular tool for adversaries to conduct post-exploitation tasks, and identifying its named pipes can reveal potential malicious activity. If confirmed malicious, this could indicate an active Cobalt Strike beacon, leading to unauthorized access, data exfiltration, or further lateral movement within the network.

• Type: TTP

• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

• Last Updated: 2024-05-16
• Author: Michael Haag, Splunk
• ID: 5876d429-0240-4709-8b93-ea8330b411b5

Annotations

ATT&CK

ATT&CK

ID	Technique	Tactic
T1055	Process Injection	Defense Evasion, Privilege Escalation

Kill Chain Phase

• Exploitation

NIST

• DE.CM

CIS20

• CIS 10

CVE

Search

`sysmon` EventID=17 OR EventID=18 PipeName IN (\\msagent_*, \\DserNamePipe*, \\srvsvc_*, \\postex_*, \\status_*, \\MSSE-*, \\spoolss_*, \\win_svc*, \\ntsvcs*, \\winsock*, \\UIA_PIPE*)  
| stats count min(_time) as firstTime max(_time) as lastTime by dest, process_name, process_id process_path, PipeName 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `cobalt_strike_named_pipes_filter`

Macros

The SPL above uses the following Macros:

• security_content_ctime
• sysmon

cobalt_strike_named_pipes_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

• _time
• EventID
• PipeName
• dest
• process_name
• process_path
• process_id

How To Implement

To successfully implement this search, you need to be ingesting logs with the process name, parent process, and command-line executions from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA.

Known False Positives

The idea of using named pipes with Cobalt Strike is to blend in. Therefore, some of the named pipes identified and added may cause false positives. Filter by process name or pipe name to reduce false positives.

Associated Analytic Story

• Trickbot
• DarkSide Ransomware
• Cobalt Strike
• BlackByte Ransomware
• Graceful Wipe Out Attack
• LockBit Ransomware

RBA

Risk Score	Impact	Confidence	Message
72.0	80	90	An instance of $process_name$ was identified on endpoint $dest$ accessing known suspicious named pipes related to Cobalt Strike.

The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

• https://attack.mitre.org/techniques/T1218/009/
• https://docs.microsoft.com/en-us/windows/win32/ipc/named-pipes
• https://hstechdocs.helpsystems.com/manuals/cobaltstrike/current/userguide/index.htm#cshid=1040
• https://www.cobaltstrike.com/blog/learn-pipe-fitting-for-all-of-your-offense-projects/
• https://gist.github.com/MHaggis/6c600e524045a6d49c35291a21e10752
• https://www.mandiant.com/resources/shining-a-light-on-darkside-ransomware-operations

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

source | version: 3