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

Static analysis result for SHA-256 a9e3ed8f4eec2bca…

MALICIOUS

Office (OLE) / .XLSX

592.5 KB
MD5: 206f39f36fb97563bba91eaf0ead9a46 SHA-1: 93da36f3078586bf18ad5ecf06be64cdc0751a4d SHA-256: a9e3ed8f4eec2bca9a8f2b2b33084439228f12c66d1d97f12d0f6c15bcdc9439
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The sample is an OOXML file that is encrypted with a default password and contains embedded OLE objects, specifically an Equation Editor object. Heuristics indicate this object is anomalous and exploits CVE-2018-0798. This suggests the file is designed to leverage the Equation Editor vulnerability for initial execution, likely to download and run a second-stage payload.

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.