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

Static analysis result for SHA-256 7ce3d708d5c0f0a6…

MALICIOUS

Office (OLE) / .XLSX

1.28 MB
MD5: d8e4f8c5d7a73b795d681aeaa027330b SHA-1: 9908f09cf063b32bf3808b7590635d98e272a28f SHA-256: 7ce3d708d5c0f0a609925844b753554fc6d0e7118346c2b1061eeb4ccc7df17b
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 embedded Equation Editor OLE object. This object appears to be a carrier for a malicious payload, indicated by an anomalous Ole10Native stream. The presence of the Equation Editor OLE object strongly suggests exploitation of a known vulnerability, likely CVE-2017-11882, to execute a secondary payload. The encryption with a default password further supports its malicious intent.

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.