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

Static analysis result for SHA-256 447530717de1dafd…

MALICIOUS

Office (OLE) / .XLSX

343.5 KB First seen: 2022-04-14
MD5: fa8a527f359a0815951dc38c4f95fe48 SHA-1: 9ef29b6f54321352d117f1af90c58213e4547625 SHA-256: 447530717de1dafdc9ac2145ce099b5adfa634d5e7fb30c14fc3852f22f2f9c3
160 Risk Score

Malware Insights

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

The file is a password-encrypted XLSX document that contains an Equation Editor OLE object. High-confidence heuristics indicate this object is designed to exploit CVE-2018-0798, a vulnerability in Microsoft Equation Editor. This exploit likely serves as a carrier for a secondary payload, though no scripts were extracted to confirm the exact delivery mechanism.

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.

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