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

Static analysis result for SHA-256 32199530a4bda250…

MALICIOUS

Office (OLE) / .XLSX

1.16 MB
MD5: 3fb2d86fd6f8e7d1b607afb13c8dc8f4 SHA-1: b2fe760f9b3462a517f684e3715c997292b13682 SHA-256: 32199530a4bda250b854cb108c71ce7c54b14b325b4d743bd308d3d657a79dcf
140 Risk Score

Malware Insights

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

The sample is an encrypted Office OOXML file that contains an embedded Equation Editor OLE object. This object is known to be used as an exploit carrier, and the anomalous Ole10Native stream suggests it is designed to deliver a second-stage payload. The encryption with a default password further indicates malicious intent.

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.