Malicious Office (OLE) / .XLSX — malware analysis report

Static analysis result for SHA-256 c87641303d21b82a…

MALICIOUS

Office (OLE) / .XLSX

1.39 MB
MD5: 9e5b18cb41885fcab6baab133280e4e4 SHA-1: 4095b67f79ac3802db3d3b5c76e931b93e06311f SHA-256: c87641303d21b82a19b4e46fb57ed82737548f2606d0bcfadb27637509ec3cc2
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.001 Malicious Link: Malicious Link T1559 Component Object Model Hijacking T1559.001 Component Object Model Hijacking: Component Object Model Hijacking

The sample is an OOXML file that is encrypted with a default password, indicating it is likely an exploit carrier. High-confidence heuristics indicate the presence of an Equation Editor OLE object, which is a common vector for exploiting Equation Editor vulnerabilities. The object contains a payload-like Ole10Native stream, suggesting it is designed to execute a secondary payload.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Default-encrypted OOXML embedded OLE object xl/embeddings/oleObject1.bin contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • Default-encrypted OOXML exploit carrier layout high OOXML_ENCRYPTED_EXPLOIT_CARRIER_SHAPE
    Default-password encrypted OOXML package contains embedded OLE object parts and additional activation/decoy parts. This layout is common in malicious Excel exploit delivery and requires inspecting the decrypted package.
  • Equation Editor object carries payload-like Ole10Native stream high OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY
    Default-encrypted OOXML embedded OLE object declares the Equation Editor CLSID but stores a large high-entropy Ole10Native stream with malformed package sizing. This is exploit-shaped Equation/OLE payload evidence.
  • Office OOXML encrypted with default VelvetSweatshop password medium OFFICE_DEFAULT_PASSWORD_ENCRYPTED_OOXML
    OLE EncryptedPackage decrypts with Excel's built-in VelvetSweatshop password. Office opens this transparently, and malware uses it to hide OOXML exploit parts from scanners that only inspect the outer OLE container.