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

Static analysis result for SHA-256 41aa359ecdec67dd…

MALICIOUS

Office (OLE) / .XLSX

1.25 MB
MD5: c00bb8a6dd6a8961b77abc75bd470c1d SHA-1: ca2769b84fec7bbbdc059c73510cd165666ccc1f SHA-256: 41aa359ecdec67dd6362b8082d3d1fcc37bcca016e8f8b491bdca26a3516a085
140 Risk Score

Malware Insights

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

The sample is an OOXML file that is encrypted with a default password and contains embedded OLE objects, specifically identified as Microsoft Equation Editor. This strongly suggests it's an exploit carrier. The Equation Editor object contains an anomalous Ole10Native stream, indicating it's likely being used to deliver a second-stage payload. No specific family could be identified, but the exploitation vector is clear.

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.