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

Static analysis result for SHA-256 af3ecba11d128fab…

MALICIOUS

Office (OLE) / .XLSX

94.5 KB First seen: 2022-04-21
MD5: df199a2fb23f72c1d3ba81586b8b25f1 SHA-1: df1f04e72d2eee27143b7bcc3425efdc3ce16c06 SHA-256: af3ecba11d128fab6e52dbf784efb83128b9aaada97a7cf2d1a659e61c8d1b46
160 Risk Score

Malware Insights

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

The sample is a password-encrypted Office document that contains an Equation Editor OLE object. Heuristics indicate this object is anomalous and specifically flags CVE-2018-0798, suggesting exploitation of a vulnerability within the Equation Editor to achieve code execution. No document body or scripts were extractable due to encryption, but the presence of the exploit carrier is sufficient for this assessment.

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.