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

Static analysis result for SHA-256 d6823f8eaf8a0720…

MALICIOUS

Office (OLE) / .XLSX

1.44 MB
MD5: 9aa0898ded04a2ee18d7b0074413ac94 SHA-1: 59c525a0dd116c9f7ec4b5773a7131ef49a29ad9 SHA-256: d6823f8eaf8a072000df7cc5811f35e58f63182657c67f7d99874d7f534851e8
140 Risk Score

Malware Insights

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

The sample is an encrypted OOXML file that contains an embedded Equation Editor OLE object. This object is known to be used as an exploit carrier, often delivering a secondary payload. The high-entropy Ole10Native stream within the Equation Editor object suggests it contains malicious content. Due to the encryption and lack of document body, the exact payload and delivery mechanism cannot be determined, but the presence of the Equation Editor OLE object strongly indicates an exploit attempt.

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.