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

Static analysis result for SHA-256 49120d38b2c2e1a1…

MALICIOUS

Office (OLE) / .XLSX

1.17 MB
MD5: 4b1c547b02f6c29c424fa933e63f3313 SHA-1: 5e3e29c974fb37cc344da7620f18991427a6201e SHA-256: 49120d38b2c2e1a11383c409db05c1df0d8694189a4946f2f1afc4d14ef813f6
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1559.001 Component Object Model Hijacking

The sample is an OOXML file that is encrypted with a default password and contains an Equation Editor OLE object. This object exhibits anomalies, including an impossible Ole10Native header and a declared inner size far exceeding the stream size, strongly indicating it carries a malicious payload. The presence of the Equation Editor OLE object points to exploitation of a vulnerability within it for initial execution.

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.