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

Static analysis result for SHA-256 1b641d6d034fcc04…

MALICIOUS

Office (OLE) / .XLSX

1.25 MB
MD5: a59729c2d7d98491f1897c3a9f1870fc SHA-1: 0155a362663b1fc12da25806f16ef7058e2944d6 SHA-256: 1b641d6d034fcc04a8686f1392974e82fce0906d7788d98d39b00010bb8e307b
140 Risk Score

Malware Insights

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

The OOXML document is encrypted with a default password and contains embedded OLE objects, specifically identified as Equation Editor objects. These objects are known exploit carriers, and the presence of an anomalous Ole10Native stream within the Equation Editor object strongly suggests it is designed to deliver a secondary payload. The file's structure and the specific heuristics fired indicate a likely attack pattern involving exploitation of the Equation Editor vulnerability for initial execution.

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.