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

Static analysis result for SHA-256 726a4f2b23c87e3d…

MALICIOUS

Office (OLE) / .XLSX

1.15 MB
MD5: c0cf90e7977e14b8bc018d7710d2092a SHA-1: cfbfbcc1758d4a52f3b97e79bcbe229a5a9fc9f3 SHA-256: 726a4f2b23c87e3dcafa0c38c2d5a31c15be0859b5fd82d2ecd6a2bc878bbc2b
160 Risk Score

Malware Insights

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

The file is an encrypted Office document containing an embedded Equation Editor OLE object, which is a known carrier for exploits. The 'OLE_EQUATION_EDITOR' and 'OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY' heuristics indicate that this object likely contains and attempts to execute a malicious payload. The document's encrypted nature and the presence of embedded OLE objects suggest it was likely delivered as a spearphishing attachment.

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.