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

Static analysis result for SHA-256 af2607b8d8e2dbcd…

MALICIOUS

Office (OLE) / .XLSX

1.21 MB
MD5: fb99dc28959b5273362b912b22e8f41a SHA-1: d9f0c5bacaa5d1827c86b603f4b2f0067e74069d SHA-256: af2607b8d8e2dbcd844cdb2a0e4b86a2a366e2fbf9c0c518c68f8d916d77a49c
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The OOXML document is encrypted with a default password and contains embedded OLE objects, specifically identified as an Equation Editor object. This object exhibits anomalies suggesting it carries a payload, indicated by the OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY heuristic. The presence of the Equation Editor OLE object strongly suggests exploitation of a vulnerability within it, likely leading to the execution of a secondary payload. The file is classified as malicious due to these exploit carrier characteristics.

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.