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

Static analysis result for SHA-256 8ce3a9fc42410936…

MALICIOUS

Office (OLE) / .XLSX

2.42 MB
MD5: 01eaf499d58262f6a48113cd3c3bba31 SHA-1: 98f5cbd078550560b11b041e8df2599fd43a1cfe SHA-256: 8ce3a9fc42410936e3ec98ca0b2b419fe9fca83379a89a5d852008220a2929f3
140 Risk Score

Malware Insights

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

The sample is an encrypted Office document that contains an Equation Editor OLE object. This object is known to be used as a carrier for exploits, specifically targeting vulnerabilities like CVE-2017-11882. The high-entropy Ole10Native stream within the Equation Editor object strongly suggests it contains a second-stage payload. The encryption and the nature of the embedded object point towards a delivery mechanism for malicious code 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.