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

Static analysis result for SHA-256 1b49f7bb0f97b336…

MALICIOUS

Office (OLE) / .XLSX

1.20 MB
MD5: adccfef0daac6e23473727bf2015dfff SHA-1: 7abb1f5b32168835019e5d8d26197998b741d499 SHA-256: 1b49f7bb0f97b3367c87c6b81979145d22313dfa6795de7413221276036c62ad
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1566 Phishing T1204.002 Malicious File

The sample is an encrypted Office OOXML file that contains an embedded Equation Editor OLE object. This object is known to be used as an exploit carrier, often delivering a second-stage payload. The presence of an 'Ole10Native' stream anomaly within the Equation Editor object strongly suggests it's designed to execute malicious code. The file is encrypted with a default password, a common tactic to evade initial static analysis.

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.