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

Static analysis result for SHA-256 85d0df94b22230e8…

MALICIOUS

Office (OLE) / .XLSX

93.5 KB First seen: 2022-04-27
MD5: 5c3cbf5f47e5de7eaa2cc559d9b44f3d SHA-1: df105810b2ac56989a48f07b423b6ad878c16a26 SHA-256: 85d0df94b22230e89ee98962d844558d8a358bdc5c519d4eaae295f98b7c6aa4
160 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The sample is a password-encrypted Office document that contains an embedded Equation Editor OLE object. High-severity heuristics indicate that this object is anomalous and likely exploits CVE-2018-0798. The presence of the Equation Editor OLE object strongly suggests exploitation for client execution. No scripts were extracted, and the document body is encrypted, limiting further analysis of the payload.

Heuristics 5

  • 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.
  • CVE-2018-0798 — anomalous Equation Editor native stream high CVE likely CVE_2018_0798_EQUATION_NATIVE_ANOMALY
    Default-encrypted OOXML contains embedded Equation Editor data with anomalous native stream bytes consistent with a CVE-2018-0798-style exploit. This is treated as likely CVE evidence because the Equation object is malformed and payload-like.
  • 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.
  • Office document is password-encrypted medium OFFICE_ENCRYPTED_PACKAGE
    OLE container holds MS-OFFCRYPTO encrypted package (Standard Encryption (Office 2007, AES)).
  • 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.