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

Static analysis result for SHA-256 487ff2bd74726474…

MALICIOUS

Office (OLE) / .XLSX

1.25 MB
MD5: 319e9ef1c334f52fd5e4d8a9f9da6bb1 SHA-1: 413e4bc23723e885d63f06964661e7e60624a58d SHA-256: 487ff2bd747264743a729a3ec0e0baad80e238768aa9c766b184affd2cf4ec6f
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1559.001 Component Object Model Hijacking

The sample is an encrypted OOXML file that contains an embedded Equation Editor OLE object. This object exhibits anomalies indicative of a payload, specifically an impossible Ole10Native header within the Equation object. This strongly suggests exploitation of a vulnerability within the Equation Editor to achieve arbitrary code execution.

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.
  • 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.
  • Equation Editor object carries payload-like Ole10Native stream high OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY
    Default-encrypted OOXML embedded OLE object declares the Equation Editor CLSID but stores a large high-entropy Ole10Native stream with malformed package sizing. This is exploit-shaped Equation/OLE payload evidence.
  • 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.