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

Static analysis result for SHA-256 fc5bf62f57c77efa…

MALICIOUS

Office (OLE) / .XLSX

1.19 MB
MD5: debc1aad4b041ea03915e01b018e5879 SHA-1: d3398c9c110eca78a10372b7d02124429d4d85c3 SHA-256: fc5bf62f57c77efa9f9264878f1753a35c27fb44bce7d9a00f8f094315355661
140 Risk Score

Malware Insights

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

The sample is an encrypted OOXML file that contains embedded OLE objects, specifically identified as an Equation Editor object. This object appears to be an exploit carrier, indicated by the OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY heuristic. The presence of the Equation Editor OLE object strongly suggests exploitation of a known vulnerability (e.g., CVE-2017-11882) to deliver a secondary payload. No document body or script content was extracted, limiting the ability to determine the exact nature of the payload or its ultimate goal.

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.