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

Static analysis result for SHA-256 fc9dd028870ac7c5…

MALICIOUS

Office (OLE) / .XLSX

392.0 KB
MD5: 4a4935f0b21078ed884aba51e0180900 SHA-1: 848e0796cea2c931bc39d92e0c763175a87b4a87 SHA-256: fc9dd028870ac7c508f0b40d747c8a5ab65a9af1da88a8f931488bee2119b505
160 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The sample is an encrypted Office document containing an embedded Equation Editor OLE object. Heuristics indicate this object is likely exploiting CVE-2018-0798, a vulnerability in Equation Editor, to execute arbitrary code. The embedded object's native stream exhibits anomalies consistent with exploit activity. The primary attack vector appears to be exploitation of the Equation Editor vulnerability for initial execution.

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.