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

Static analysis result for SHA-256 654020f2936ac35a…

MALICIOUS

Office (OLE) / .XLSX

43.5 KB
MD5: a50519badf2e0d5bd74ecc73b312d231 SHA-1: 7ddbd2cd684136ae10107c7d4ee4a5c3ba153860 SHA-256: 654020f2936ac35a44528062ea745fc1cc45b79920c23c54d2528cddcdaf940c
160 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The sample is an encrypted Office document containing an Equation Editor OLE object. Heuristics indicate this object is anomalous and likely exploits CVE-2018-0798, a known vulnerability allowing for arbitrary code execution when the object is loaded. The encrypted nature and the presence of an exploit carrier shape strongly suggest this document is designed to deliver a malicious 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.