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

Static analysis result for SHA-256 86ff6dbc46b3192a…

MALICIOUS

Office (OLE) / .XLSX

100.0 KB First seen: 2022-09-13
MD5: c97df51b661f8aee81e084c24c0b8a5d SHA-1: df81395c869d25df0598517e29818654e9523147 SHA-256: 86ff6dbc46b3192a621c6accd6f57be0ac6c2f3407ec7b34149ec64a61c9b646
160 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1559.001 Component Object Model Hijacking

The sample is an encrypted Office document that contains an Equation Editor OLE object. Heuristics indicate this object is anomalous and exploits CVE-2018-0798, a known vulnerability in the Equation Editor. This suggests the file is an exploit carrier designed to execute arbitrary code.

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-128)).
  • 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.