Suspicious TransferLoader C2 User-Agent Strings (via proxy)

PremiumReviewedSigma · High · v1
Category
proxy
Author
HuntRule
Published
2026-11-06
Updated
2026-11-06

ATT&CK techniques

C2
  1. Recon

  2. Resource Dev

  3. Initial Access

  4. Execution

  5. Persistence

  6. Priv Esc

  7. Defense Evasion

  8. Cred Access

  9. Discovery

  10. Lateral Movement

  11. Collection

  12. Exfiltration

  13. Impact

What it detects

This rule detects outbound web requests using the hardcoded TransferLoader user-agent strings that the loader sends when contacting its command and control servers. Genuine browsers do not present these short static agent strings.

Related detections9 linkedT1071.001 — drag to rearrange
Suspicious CoffeeLoader C2 Beacon With Spoofed iPhone User-Agent (via proxy)
Malicious C2 Communication via M-RED-TEAM User Agent (via proxy)
Suspicious Bash Reverse Shell via Dev TCP Redirection
Malicious TeamPCP antv Backup C2 Domain m-kosche (via dns_query)
Malicious Axios npm Compromise C2 Beacon to sfrclak and callnrwise (via dns_query)
Malicious TeamPCP durabletask C2 git-service and m-kosche (via dns_query)
Possible PowerShell Empire Default C2 URI Beaconing
Malicious GhostLocker Ransomware C2 Communication via HTTP (via proxy)
Malicious Agent Tesla Loader Malformed User-Agent in HTTP Traffic (via proxy)
Suspicious TransferLoader C2 User-Agent Strings (via proxy)
Pivot detection · T1071.001 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.