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

Static analysis result for SHA-256 4ce8c618568fa28a…

MALICIOUS

Office (OLE) / .XLSX

1.30 MB
MD5: 2c8e85e32a1555e54b35e6255c4a8fcd SHA-1: 5356b410a7b310616b8417f1231d5f4a827d8f09 SHA-256: 4ce8c618568fa28a0877067bd09d1aa6681fc3937ffc6c2bb2e6b527c9e24c64
140 Risk Score

Malware Insights

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

The sample is an encrypted Excel file that contains an embedded Equation Editor OLE object. This object exhibits anomalies in its Ole10Native stream size and entropy, strongly suggesting it is a carrier for a malicious payload. The presence of the Equation Editor OLE object is a common indicator of exploits targeting vulnerabilities within that component.

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.