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

Static analysis result for SHA-256 e3469b3d96e63161…

MALICIOUS

Office (OLE) / .XLSX

1.27 MB
MD5: 643fc978b1f9e32668a88202a7091266 SHA-1: ee970a6713bd017fd118a1eb54a237339c4fd579 SHA-256: e3469b3d96e6316114395abe8caef91aa9ac9edac2d701c2d64981d3c0dfc5f0
140 Risk Score

Malware Insights

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

The sample is an encrypted OOXML file that contains an Equation Editor OLE object. This object is known to be used as an exploit carrier for vulnerabilities such as CVE-2017-11882. The OLE object contains a malformed Ole10Native stream, indicating it likely carries a second-stage payload. No document body or scripts were extracted, but the presence of the Equation Editor exploit carrier is a strong indicator of 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.