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

Static analysis result for SHA-256 bf4f5431f4556ef2…

MALICIOUS

Office (OLE) / .XLSX

1.21 MB
MD5: 85b0de76fb89e50348b02b6ad72925ff SHA-1: 0b76fb0ab558cce65282af9ed9f153cc0ff43082 SHA-256: bf4f5431f4556ef240e6f9084268e17d9417453ed1d9593bcfcf6535fb97c80c
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious File T1559.001 Component Object Model T1204.002 Malicious File: User Execution

The file is an encrypted OOXML document that utilizes a default password, a common technique for hiding malicious content. High-severity heuristics indicate the presence of an Equation Editor OLE object, which is known to be exploited. This object contains an anomalous Ole10Native stream, suggesting it carries a payload. The combination of these factors points to an exploit carrier designed to leverage the Equation Editor vulnerability.

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.