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

Static analysis result for SHA-256 0e8eb65966b1b26f…

MALICIOUS

Office (OLE) / .XLSX

1.02 MB
MD5: 99ea279fbcfa0af20a5bf1a9a2ed9201 SHA-1: b2d9cceae8bd961e43ed146ab136aaacc57ae565 SHA-256: 0e8eb65966b1b26fcaa9aa06bacc4df9b0f689b63063c0118e42c5057bb1649e
160 Risk Score

Malware Insights

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

The sample is a password-protected OOXML file identified as an exploit carrier. It contains an Equation Editor OLE object which is known to be used for exploiting vulnerabilities. The presence of an anomalous Ole10Native stream within the Equation Editor object suggests it is designed to deliver a second-stage payload, likely via exploitation for client execution.

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.