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

Static analysis result for SHA-256 14a205b84909c713…

MALICIOUS

Office (OLE) / .XLSX

71.6 KB First seen: 2022-06-20
MD5: 290e3081c48b78d03046c34ed73248c7 SHA-1: db501782eb1628739c9568d176b7e1d3c71f4ac2 SHA-256: 14a205b84909c713e56c7e91b52818f380c6846dc7742d8cc5784246e3d98ee5
180 Risk Score

Malware Insights

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

The file is an encrypted OOXML document that contains an Equation Editor OLE object, a common carrier for exploits. The presence of 'OLE_EQUATION_EDITOR' and 'OOXML_ENCRYPTED_EXPLOIT_CARRIER_SHAPE' heuristics strongly suggests exploitation of a known vulnerability within Equation Editor to achieve code execution. The document's encrypted nature and lack of extractable plaintext indicate it's designed to obscure its malicious 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.