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

Static analysis result for SHA-256 9533a57de211ba22…

MALICIOUS

Office (OLE) / .XLSX

1.29 MB
MD5: 4b79e0b292388c830e71dd54a38d5725 SHA-1: ffc2c99cb8eb3bbd5f978665aa8cb5811c2df025 SHA-256: 9533a57de211ba22034a632e24ad84474cb8340ac961fab9c295d0ebe6b127c0
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1566 Phishing T1204.001 Malicious Link: Malicious File 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 a carrier for exploits, specifically targeting vulnerabilities like CVE-2017-11882. The presence of an 'Ole10Native' stream within the Equation Editor object suggests it's designed to deliver a secondary payload. The default encryption password further indicates a lack of legitimate use.

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.