Sigma rule: Kalambur Backdoor Curl TOR SOCKS Proxy Execution

Rule

Title

Kalambur Backdoor Curl TOR SOCKS Proxy Execution

Status

experimental

Level

high

Author

Arda Buyukkaya (EclecticIQ)

Date

2025-02-11

File

rules-emerging-threats/2025/Malware/proc_creation_win_malware_kalambur_curl_socks_tor.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects the execution of the "curl.exe" command, referencing "SOCKS" and ".onion" domains, which could be indicative of Kalambur backdoor activity.

Log source

product

windows

category

process_creation

Detection

selection_img:
    Image|endswith: '\curl.exe'
selection_socks:
    CommandLine|contains:
        - 'socks5h://'
        - 'socks5://'
        - 'socks4a://'
selection_onion:
    CommandLine|contains: '.onion'
condition: all of selection_*

False positives (as the rule lists them)

• Unlikely

Tags

• attack.execution
• attack.command-and-control
• attack.t1090
• attack.t1573
• attack.t1071.001
• attack.t1059.001
• attack.s0183
• detection.emerging-threats

MITRE ATT&CK ids this rule names

• S0183
• T1059.001
• T1071.001
• T1090
• T1573

References

• https://blog.eclecticiq.com/sandworm-apt-targets-ukrainian-users-with-trojanized-microsoft-kms-activation-tools-in-cyber-espionage-campaigns

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/2025/Malware/proc_creation_win_malware_kalambur_curl_socks_tor.yml