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

Static analysis result for SHA-256 c180d80c2eed81cc…

MALICIOUS

Office (OLE) / .XLSX

186.5 KB First seen: 2022-05-02
MD5: 8b3f1fced421bff11a2c787e21abe865 SHA-1: 298e20cc84f76944df05279d2561ff31591eef8a SHA-256: c180d80c2eed81ccc60e84ce45a69f22a9d98d9c99b6df2b9cb6a404abef9cea
160 Risk Score

Malware Insights

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

The file is a password-encrypted Office document containing an embedded Equation Editor OLE object. Heuristics indicate this object is anomalous and specifically triggers on CVE-2018-0798, suggesting it's designed to exploit this vulnerability for initial execution. The encrypted nature and the presence of an exploit carrier shape point towards a malicious intent to deliver a secondary 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.