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

Static analysis result for SHA-256 6b8fb4d4e872cf97…

MALICIOUS

Office (OLE) / .XLSX

587.8 KB
MD5: 5e3cfa8a71fbefaeedfc0d3dbe9f7c51 SHA-1: 34bf9b8b6c46cfe5ef624cbded56f2d59e1e59d3 SHA-256: 6b8fb4d4e872cf97e4e4943a9eee6a6d8175f518c039fdc066caae45b21fc5a8
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, a common technique to evade static analysis. The presence of an Equation Editor OLE object (CLSID offset 0x450) strongly suggests exploitation of a known vulnerability within that component. The document's encrypted nature and malformed structure indicate it's designed to carry and execute a secondary payload.

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.