Emerging Threatcriticaltest
Serv-U Exploitation CVE-2021-35211 by DEV-0322
Detects patterns as noticed in exploitation of Serv-U CVE-2021-35211 vulnerability by threat group DEV-0322
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Launch
Florian Roth (Nextron Systems)Created Wed Jul 14Updated Sun Dec 1875578840-9526-4b2a-9462-af469a45e7672021
Emerging Threat
Active Threat
Developed to detect an active or emerging threat. Prioritize investigation of any alerts and correlate with threat intelligence.
Log Source
WindowsProcess Creation
ProductWindows← raw: windows
CategoryProcess Creation← raw: process_creation
Events generated when a new process is spawned on the system. Covers command-line arguments, parent/child relationships, and process metadata.
Detection Logic
Detection Logic3 selectors
detection:
selection_whoami:
CommandLine|contains: 'whoami'
selection_cmd_1:
CommandLine|contains:
- './Client/Common/'
- '.\Client\Common\'
selection_cmd_2:
CommandLine|contains: 'C:\Windows\Temp\Serv-U.bat'
condition: selection_whoami and 1 of selection_cmd*False Positives
Unlikely
False positives are unlikely for most environments. High confidence detection.
References
MITRE ATT&CK
Tactics
Sub-techniques
Other
cve.2021-35211detection.emerging-threats
Rule Metadata
Rule ID
75578840-9526-4b2a-9462-af469a45e767
Status
test
Level
critical
Type
Emerging Threat
Created
Wed Jul 14
Modified
Sun Dec 18
Path
rules-emerging-threats/2021/Exploits/CVE-2021-35211/proc_creation_win_exploit_cve_2021_35211_servu.yml
Raw Tags
attack.persistenceattack.t1136.001cve.2021-35211detection.emerging-threats