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

Static analysis result for SHA-256 3998b3f6a81b9b52…

MALICIOUS

Office (OLE) / .XLSX

1.26 MB
MD5: 5007810d358c61adc260ec06e1a7ab28 SHA-1: a1956036cce1257cc0de83ebb8d81136b8b68870 SHA-256: 3998b3f6a81b9b52fa9aa4b84f34dbcaf3cdf884522a32371f6951400d080356
160 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File: User Execution T1559.001 Component Object Model Hijacking

The sample is an encrypted Office XLSX file. High-severity heuristics indicate the presence of an Equation Editor OLE object, which is a known carrier for exploits. The object contains an anomalous Ole10Native stream, suggesting it is designed to deliver a payload. The encryption and the specific OLE object point towards a malicious document designed for exploitation.

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.