UNC4841 - SSL Certificate Exfiltration Via Openssl
Detects the execution of "openssl" to connect to an IP address. This techniques was used by UNC4841 to exfiltrate SSL certificates and as a C2 channel with named pipes. Investigate commands executed in the temporal vicinity of this command.
Detection logic
selection
Image|endswith: /openssl
CommandLine|re: "[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}\\.[0-9]{1,3}"
CommandLine|contains|all:
- s_client
- -quiet
- -connect
CommandLine|contains:
- :443
- :8080Condition
selectionRaw YAML
title: UNC4841 - SSL Certificate Exfiltration Via Openssl
id: 60911c07-f989-4362-84af-c609828ef829
status: test
description: Detects the execution of "openssl" to connect to an IP address. This techniques was used by UNC4841 to exfiltrate SSL certificates and as a C2 channel with named pipes. Investigate commands executed in the temporal vicinity of this command.
references:
- https://www.mandiant.com/resources/blog/barracuda-esg-exploited-globally
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-06-16
tags:
- attack.stealth
- attack.t1140
- detection.emerging-threats
logsource:
product: linux
category: process_creation
detection:
selection:
Image|endswith: '/openssl'
CommandLine|re: '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}'
CommandLine|contains|all:
- 's_client'
- '-quiet'
- '-connect'
CommandLine|contains:
- ':443'
- ':8080'
condition: selection
falsepositives:
- Unknown
level: highFalse positives
- Unknown