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

Static analysis result for SHA-256 bf1135a0294f09a2…

MALICIOUS

Office (OLE) / .XLSX

406.5 KB
MD5: 91cf1d6f9808272ca31add03fad8defc SHA-1: df35c27f2186c840e6fefaa6d2e498b9373d8880 SHA-256: bf1135a0294f09a274ccfc7c3dcdbb4331a2aa7fe22cc35a12c14285d62c7a88
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The sample is an encrypted OOXML file that contains an embedded Equation Editor OLE object. Heuristics indicate exploitation of CVE-2018-0798 via this object, which is a known method for delivering malicious payloads. No document body or scripts were extractable, but the presence of the Equation Editor exploit carrier strongly suggests a client-side execution attack.

Heuristics 4

  • 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 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.