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

Static analysis result for SHA-256 bf48d2f277908894…

MALICIOUS

Office (OLE) / .XLSX

78.0 KB First seen: 2022-06-21
MD5: 40b1f04ae9382c432b8b3ce0b7e9444e SHA-1: 20c66c15ea2c6f0b6a42d829064fe94d86153fa0 SHA-256: bf48d2f27790889444f1f8d252a29b5c43d443fb4f8e04fa18a74da922f02485
160 Risk Score

Malware Insights

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

The file is an encrypted Office document, indicated by the 'OFFICE_ENCRYPTED_PACKAGE' and 'OFFICE_DEFAULT_PASSWORD_ENCRYPTED_OOXML' heuristics. The presence of an 'Equation Editor OLE object' and the 'CVE_2018_0798_EQUATION_NATIVE_ANOMALY' heuristic strongly suggest exploitation of CVE-2018-0798 via the Equation Editor component. This is further supported by the 'OOXML_ENCRYPTED_EXPLOIT_CARRIER_SHAPE' heuristic pointing to an exploit carrier within the OLE object. The document is likely intended to deliver a malicious payload through this exploit.

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.
  • CVE-2018-0798 — anomalous Equation Editor native stream high CVE likely CVE_2018_0798_EQUATION_NATIVE_ANOMALY
    Default-encrypted OOXML contains embedded Equation Editor data with anomalous native stream bytes consistent with a CVE-2018-0798-style exploit. This is treated as likely CVE evidence because the Equation object is malformed and payload-like.
  • 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.

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