Sigma rule: Potential MOVEit Transfer CVE-2023-34362 Exploitation - Dynamic Compilation Via Csc.EXE

Rule

Title

Potential MOVEit Transfer CVE-2023-34362 Exploitation - Dynamic Compilation Via Csc.EXE

Status

test

Level

medium

Author

@kostastsale

Date

2023-06-01

File

rules-emerging-threats/2023/Exploits/CVE-2023-34362-MOVEit-Transfer-Exploit/proc_creation_win_exploit_cve_2023_34362_moveit_transfer_exploitation_activity.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects the execution of "csc.exe" via "w3wp.exe" process. MOVEit affected hosts execute "csc.exe" via the "w3wp.exe" process to dynamically compile malicious DLL files.

MOVEit is affected by a critical vulnerability. Exploited hosts show evidence of dynamically compiling a DLL and writing it under C:\\Windows\\Microsoft\.NET\\Framework64\\v4\.0\.30319\\Temporary ASP\.NET Files\\root\\([a-z0-9]{5,12})\\([a-z0-9]{5,12})\\App_Web_[a-z0-9]{5,12}\.dll.

Hunting Opportunity

Events from IIS dynamically compiling binaries via the csc.exe on behalf of the MOVEit application, especially since May 27th should be investigated.

Log source

product

windows

category

process_creation

Detection

selection:
    ParentImage|endswith: '\w3wp.exe'
    ParentCommandLine|contains: 'moveitdmz pool'
    Image|endswith: '\csc.exe'
condition: selection

False positives (as the rule lists them)

• Initial software installation and software updates.

Tags

• attack.execution
• attack.t1059
• cve.2023-34362
• detection.emerging-threats

CVEs this rule names

• CVE-2023-34362

MITRE ATT&CK ids this rule names

• T1059

References

• https://www.huntress.com/blog/moveit-transfer-critical-vulnerability-rapid-response
• https://www.trustedsec.com/blog/critical-vulnerability-in-progress-moveit-transfer-technical-analysis-and-recommendations/

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules-emerging-threats/2023/Exploits/CVE-2023-34362-MOVEit-Transfer-Exploit/proc_creation_win_exploit_cve_2023_34362_moveit_transfer_exploitation_activity.yml