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

Static analysis result for SHA-256 39f71db5d9a883ce…

MALICIOUS

Office (OLE) / .XLSX

1.37 MB
MD5: dede35bbd852933529ed2b6e9c67d7fc SHA-1: 1d8e2dc086aea5dff3a4e83521ddcb90b6bd02ca SHA-256: 39f71db5d9a883cee88c17e50b42e790b307d67487e2a26601abf445c04a7e90
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File: User Execution T1559.001 Component Object Model Hijacking

The sample is an OOXML file that is encrypted with a default password and contains embedded OLE objects, specifically identified as an Equation Editor exploit carrier. The presence of an Equation Editor OLE object with a payload-like Ole10Native stream strongly suggests exploitation of a known vulnerability within this component to deliver a secondary payload. No specific IOCs were extracted, but the attack pattern is clear.

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.