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

Static analysis result for SHA-256 f28cc9d3bbd4a373…

MALICIOUS

Office (OLE) / .XLSX

1.19 MB
MD5: fe2e03f43ba183428946e43f8d8471ec SHA-1: 94ccc19156a44488a2e79f975fa67c880d83d19a SHA-256: f28cc9d3bbd4a3730c410a93b0566922aa32479af5784ebcd479afbd80791e0c
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The sample is an OOXML file encrypted with a default password, indicating it's likely an exploit carrier. High-severity heuristics indicate the presence of an Equation Editor OLE object, a known vector for delivering malicious payloads. The Equation Editor object contains an anomalous Ole10Native stream, suggesting it's designed to execute code. The file's structure and heuristics strongly point to exploitation of the Equation Editor vulnerability 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.