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

Static analysis result for SHA-256 4da5cb33b2f19fc2…

MALICIOUS

Office (OLE) / .XLSX

93.5 KB First seen: 2022-05-13
MD5: 70583aa55602c8ba0a7f85d815cb5806 SHA-1: 7123adf1a048a8168457dcb5aaa9fead90e40218 SHA-256: 4da5cb33b2f19fc2d80cafe3e9e9f1a7071d65724ea9316c86c1a635105bab44
160 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.002 Malicious File T1059 Command and Scripting Interpreter

The sample is a password-encrypted Office document containing an Equation Editor OLE object. Heuristics indicate this object is an exploit carrier for CVE-2018-0798, a vulnerability in Microsoft Equation Editor. The exploit likely leads to the execution of a second-stage payload, though no specific details of the payload or its delivery mechanism were extracted.

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.