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

Static analysis result for SHA-256 f25a3df2dc1d74c6…

MALICIOUS

Office (OLE) / .XLSX

1.30 MB
MD5: e4f8fe5b1214945e4f9253ff5a019030 SHA-1: 3151fd3bea5a082c78fbdea2544fe7de09015587 SHA-256: f25a3df2dc1d74c6bd66ffb87c8b48f2393b0a84239f27121f323ad0dd561fdf
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment 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, specifically for vulnerabilities like CVE-2017-11882. The 'OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY' heuristic indicates that the Equation Editor object contains a payload-like stream, suggesting it's designed to drop and execute a secondary malicious component. No specific family could be identified, but the delivery mechanism is consistent with macro-based or exploit-laden Office documents.

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.