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

Static analysis result for SHA-256 4bf41bb980a5c5a5…

MALICIOUS

Office (OLE) / .XLSX

52.5 KB First seen: 2022-06-17
MD5: 67291fdcbd2d5208599ca3927f6eba42 SHA-1: bc525ca1a1b5b30470878cbafdb1635c5e39cfd4 SHA-256: 4bf41bb980a5c5a52dece41283207fae3519ee20cb5ec7f0947f63a0166b9e4b
160 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.002 Malicious Link: Malicious File T1559.001 Component Object Model Hijacking: Component Object Model T1059 Command and Scripting Interpreter

The sample is an encrypted Office document, identified as an exploit carrier due to the presence of an Equation Editor OLE object. The high-confidence heuristics indicate exploitation of CVE-2018-0798 via an anomalous Equation Editor native stream within the 'oleObject1.bin' embedded object. This suggests the document is designed to exploit this vulnerability upon opening, likely leading to the execution of 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.
  • 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.