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

Static analysis result for SHA-256 7fe27a3d98514bf3…

MALICIOUS

Office (OLE) / .XLSX

1.28 MB
MD5: d9fa43cb02cc9264f9bd1cff74c7c414 SHA-1: 6e990d83d78ecbeb6b09414302e9cc9e92b54c34 SHA-256: 7fe27a3d98514bf33e4f5aede5a6d530b35d901938f2fff96d0def9017e8039a
140 Risk Score

Malware Insights

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

The sample is an encrypted OOXML file that utilizes embedded OLE objects, specifically targeting the Equation Editor (CLSID offset 0x450). The presence of an anomalous Ole10Native stream within the Equation Editor object suggests it's being used as a carrier for a malicious payload. The high entropy of the stream further supports this. The file is likely designed to exploit the Equation Editor vulnerability to execute a secondary payload.

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.