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

Static analysis result for SHA-256 6f7e3b8669f1d481…

MALICIOUS

Office (OLE) / .XLSX

936.0 KB
MD5: 35bf2857cd5f846c8b9d0e02316b37d7 SHA-1: 337232690f3c896c3eda309ca6356f72f6580679 SHA-256: 6f7e3b8669f1d48156b3bdcf959a5a23fce48fa9ee8d7be037a1b1564a27599e
180 Risk Score

Malware Insights

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

The file is a password-encrypted OOXML document that contains an embedded Equation Editor OLE object. This combination strongly suggests it is designed to exploit a vulnerability within the Equation Editor to execute arbitrary code. The encryption and malformed structure indicate an attempt to evade static analysis, further supporting a malicious intent.

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.
  • Encrypted Office package with CFB FAT corruption critical OLE_ENCRYPTED_AND_MALFORMED
    Encrypted-package shape co-occurs with FAT-chain corruption — the documented combined evasion form.
  • 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.
  • Office document is password-encrypted medium OFFICE_ENCRYPTED_PACKAGE
    OLE container holds MS-OFFCRYPTO encrypted package (Standard Encryption (Office 2007, AES)).
  • 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.