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

Static analysis result for SHA-256 42fdb467134ce81a…

MALICIOUS

Office (OLE) / .XLSX

1.22 MB
MD5: 7b2bc753479a1b7d0a12b2cb9eff2afa SHA-1: 24f542d7252f1807bf44945f6e0d2f3b4dfbc2bd SHA-256: 42fdb467134ce81a76e10646d592d4b67a8c7fc8ba1da56d57087d8e5c5f1953
140 Risk Score

Malware Insights

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

The sample is an encrypted OOXML file that contains an Equation Editor OLE object, a known carrier for exploits. The 'OLE_EQUATION_EDITOR' and 'OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY' heuristics indicate that this object is likely being used to deliver a malicious payload. The file is encrypted with a default password, suggesting a common exploit delivery technique.

Heuristics 4

  • 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.
  • 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.
  • Equation Editor object carries payload-like Ole10Native stream high OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY
    Default-encrypted OOXML embedded OLE object declares the Equation Editor CLSID but stores a large high-entropy Ole10Native stream with malformed package sizing. This is exploit-shaped Equation/OLE payload evidence.
  • 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.