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

Static analysis result for SHA-256 e9ec93346ae4b739…

MALICIOUS

Office (OLE) / .XLSX

343.5 KB First seen: 2022-04-11
MD5: 5c50af4a569b90d891835979b3a7ad1f SHA-1: 657176ee2be8ff0affc7cb18966a374609fd27c0 SHA-256: e9ec93346ae4b739eab87def92a7bb0f6ec3aa10d7e9a023cfc288f206e6ef72
160 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The sample is a password-encrypted Office document containing an Equation Editor OLE object. Heuristics indicate this object is anomalous and specifically flags CVE-2018-0798, suggesting exploitation of a vulnerability within the Equation Editor. The presence of OLE streams like 'xl/embeddings/oleObject1.bin' further supports this attack vector. The exact payload or execution method is not directly discernible from the provided static analysis, but the exploitation of Equation Editor is a common delivery mechanism for various malware families.

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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