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

Static analysis result for SHA-256 5e9b6256c2adafe0…

MALICIOUS

Office (OLE) / .XLSX

1.37 MB
MD5: 2e75248bf9decdb8d02c9e69ac261a61 SHA-1: 45f584d63706026e963cbb5b7242a4bc130efee7 SHA-256: 5e9b6256c2adafe03e928b0afe98328a3d77c69c6f924d2608e9daf131063d9f
160 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The sample is a password-encrypted OOXML file identified as an exploit carrier. It contains an Equation Editor OLE object which is known to be used for delivering malicious payloads. The presence of an 'Ole10Native' stream within the Equation Editor object, coupled with an anomaly in its header and size, strongly suggests it contains an embedded exploit. This exploit likely facilitates client-side execution, and the file itself would typically be delivered via spearphishing.

Heuristics 5

  • 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 document is password-encrypted medium OFFICE_ENCRYPTED_PACKAGE
    OLE container holds MS-OFFCRYPTO encrypted package (Standard Encryption (Office 2007+, AES-128)).
  • 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.

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