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

Static analysis result for SHA-256 487d89d2b1882c15…

MALICIOUS

Office (OLE) / .XLSX

1.12 MB
MD5: 8dda38e45729f25cefc7c67d1dbd84cd SHA-1: a3effec238377911061089e20e40b3cc4ecc043f SHA-256: 487d89d2b1882c1525df20d4cdb9f5ae62963c1cccda26f3e7989c8e21438ec9
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.002 Phishing: Spearphishing Attachment

The sample is an OOXML file that is encrypted with a default password and contains an embedded Equation Editor OLE object. This object is known to be used as an exploit carrier, specifically for delivering malicious payloads. The presence of an 'Ole10Native' stream within the Equation Editor object, with an anomalous header and size discrepancy, strongly indicates it contains an embedded executable payload. The exploitation of the Equation Editor is a common technique 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.