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

Static analysis result for SHA-256 296f6554dbc9f1a9…

MALICIOUS

Office (OLE) / .XLSX

2.40 MB
MD5: e26d11ab08b588b3ae74294f6f50382c SHA-1: 8ac7495693385580a481b6b60b6de1c16d3d0702 SHA-256: 296f6554dbc9f1a9088cd3ae718daa63c591c39c5c45779733bf5296bff1ecd0
140 Risk Score

Malware Insights

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

The file is an encrypted Office XLSX document that contains an embedded Equation Editor OLE object. This object is known to be used as an exploit carrier, and the anomaly detected in the Ole10Native stream suggests it contains a malicious payload. The encryption and the use of the Equation Editor point towards a common delivery mechanism for exploiting vulnerabilities.

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.