huntrule

Windows DLL Sideloading: CCleanerReactivator.dll Loaded from CCleaner Directories

Identifies potential CCleanerReactivator.dll DLL sideloading when loaded by CCleanerReactivator.exe outside expected CCleaner paths.

FreeReviewedSigma · Medium · v2
Product
windows
Category
image_load
Author
X__Junior (SigmaHQ), DRL 1.1
Published
2023-07-13
Updated
2026-07-31
AnalysisDetection

ATT&CK techniques

Execution → Defense Evasion

  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. C2

  13. Exfiltration

  14. Impact

What it detects

Flags Windows processes that load CCleanerReactivator.dll from an image path ending with \\CCleanerReactivator.dll while the loader executable matches CCleanerReactivator.exe in common CCleaner install locations. DLL sideloading is a stealthy way for an attacker to run malicious code by planting or swapping a DLL that a legitimate executable expects. The rule relies on image load telemetry, matching the loaded DLL name and the loading process path under Program Files locations.

Reporting behind it

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Suspicious Encrypted Implant File Creation for DLL Search Order Hijacking (RainyDay Turian PlugX)
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Malicious dal_keepalives.dll Sideloaded By Signed Binary (via image_load)
Suspicious Cortex XDR Binary Sideloading winutils.dll (via image_load)
Windows DLL Sideloading: CCleanerReactivator.dll Loaded from CCleaner Directories
Pivot detection · T1574.001 · 9 related

Changelog

v2
  1. v2
    Candidate ingested via manual entry.2026-07-31
  2. v1
    No changelog recorded for this version.2026-07-30

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