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

Static analysis result for SHA-256 2343ad8cbaec4cfc…

MALICIOUS

Office (OLE) / .XLSX

1.26 MB
MD5: 05ba25a02dacce0d5516e22623156649 SHA-1: 85551c311f2b3c8e2bb4fd2394236b0d8a18bb13 SHA-256: 2343ad8cbaec4cfc723e45aff2d9bd2da9ad95f13c846a339f9ffa2ce0c58ec4
140 Risk Score

Malware Insights

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

The sample is an encrypted Office XLSX file that contains an embedded Equation Editor OLE object. This object is known to be used as a carrier for exploits, and the anomaly detected in the Ole10Native stream suggests it contains a payload. The default encryption further indicates a malicious intent to obscure the contents. No specific family could be identified, but the technique points towards a common exploit delivery method.

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.