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

Static analysis result for SHA-256 e2ba9fe3bc223a58…

MALICIOUS

Office (OLE) / .XLSX

327.5 KB
MD5: ddb57c15a6edbd9e2acdab76a2aa6688 SHA-1: 13a6123fdf046374395bb55e4d6b9eb4cbe3b655 SHA-256: e2ba9fe3bc223a5862f0e56371f39f207e15427941a07fcf0a1241aaeb2e53a8
160 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The sample is a password-encrypted Excel file containing an embedded Equation Editor OLE object. Heuristics indicate this object is anomalous and exploits CVE-2018-0798, a vulnerability in Equation Editor. This suggests the file is designed to exploit this vulnerability for initial execution, likely leading to the download and execution of a second-stage 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-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.