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

Static analysis result for SHA-256 a23425be1b641653…

MALICIOUS

Office (OLE) / .XLSX

343.4 KB
MD5: ce669e849499691c572cae1e22fafbbb SHA-1: 7a982e6229963bee82669d014f63729f85040f8a SHA-256: a23425be1b64165391c27a65db8082855a16057655f6a76fa208c39861f6e279
180 Risk Score

Malware Insights

MITRE ATT&CK
T1559.001 Component Object Model Hijacking T1204.002 Malicious File

The sample is an encrypted Excel spreadsheet that utilizes an embedded OLE object, specifically targeting Equation Editor. This combination strongly suggests it's designed to deliver a malicious payload by exploiting a known vulnerability within the Equation Editor component. The encryption and malformed structure further indicate an attempt to evade detection.

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.