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

Static analysis result for SHA-256 daf9c4fb16137d18…

MALICIOUS

Office (OLE) / .XLSX

1.16 MB
MD5: bf3a50651b57dedf4b8590990278f100 SHA-1: 63ce109db6e427b012d48b1fc4345aa0d12ab828 SHA-256: daf9c4fb16137d18aa10adfd405826569d158d587c8b559f61bf4cbd92fbeed7
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 Equation Editor OLE object. This object exhibits anomalies suggesting it carries a payload, a common technique for exploiting vulnerabilities like CVE-2017-11882. The high entropy of the Ole10Native stream further supports the presence of executable content. No specific family could be identified, and no further IOCs were extracted.

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.