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

Static analysis result for SHA-256 44c1b4cc8058b6b8…

MALICIOUS

Office (OLE) / .XLSX

379.0 KB
MD5: 46e6af996d67d4aa6492126ab99fbbf1 SHA-1: c2a947396c9f92cc3c0b3d3fd65494c83776a5b4 SHA-256: 44c1b4cc8058b6b809796292e347516cd5d84af6f9b63eb6791c3ee5f38cc11d
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The sample is an encrypted OOXML file that contains an Equation Editor OLE object. Heuristics indicate exploitation of CVE-2018-0798 via this object. The default encryption and the presence of multiple OLE objects suggest it's designed to deliver a secondary payload, likely through the exploited Equation Editor component.

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.