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

Static analysis result for SHA-256 4694b353fffea741…

MALICIOUS

Office (OLE) / .XLSX

379.7 KB First seen: 2022-06-09
MD5: 735e3f82a379fa0f66b91c83fd173765 SHA-1: f22b1b0554bbb4160bbf1b769c7445129fbb0424 SHA-256: 4694b353fffea741a2570e9f10c62fb3cb207d96371c542cc56147a9ab46eafa
180 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample is an encrypted Office document, flagged as malicious due to multiple high and critical heuristics. Specifically, it contains an Equation Editor OLE object within an encrypted OOXML exploit carrier, indicating it's designed to leverage a vulnerability. The encryption prevents direct analysis of the document body, but the presence of the Equation Editor OLE object strongly suggests an exploit delivery mechanism.

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.