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

Static analysis result for SHA-256 8d0ff95405ce9a8a…

MALICIOUS

Office (OLE) / .XLSX

1.34 MB
MD5: 5bf999f74574d83a0cf2a1dd194a4bf3 SHA-1: be8f4f3a942dfe76f95571c3e7405a98931b9147 SHA-256: 8d0ff95405ce9a8a7e23a3d1bd7f7cab0bdeb2f13e88d6dd034a59cb7313742e
140 Risk Score

Malware Insights

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

The sample is a default-encrypted OOXML file containing an Equation Editor OLE object. This object exhibits an anomaly where it carries a payload-like Ole10Native stream, indicating it's likely being used to exploit a known vulnerability in the Equation Editor component for initial execution. The file's encryption and the presence of the exploit carrier strongly suggest it's designed to deliver a secondary malicious payload.

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.