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

Static analysis result for SHA-256 3bf9d2dfe00be48f…

MALICIOUS

Office (OLE) / .XLSX

80.0 KB First seen: 2022-06-27
MD5: 25bc54362768f49e619468836b084dd6 SHA-1: 728e290bd05e1b96e6ac153e3cb260346c83c598 SHA-256: 3bf9d2dfe00be48f31af920f3e857f4a0dee0e68bf1838caff3c90205a292a7e
160 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The sample is an encrypted Office document that contains an Equation Editor OLE object. Heuristics indicate that this object is anomalous and specifically related to CVE-2018-0798, suggesting it's designed to exploit a vulnerability in the Equation Editor for client execution. No document body or scripts were extractable due to encryption, but the presence of the exploit carrier is sufficient evidence.

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.