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

Static analysis result for SHA-256 41485c5877811031…

MALICIOUS

Office (OLE) / .XLSX

1.49 MB
MD5: d2a41dabec8a781e219afc2eb6757fc6 SHA-1: 529d279ad92b65dfb63e75e51741eeb00bd87314 SHA-256: 41485c58778110315f66d2176f6403c5f2ef2e873b7478e5471915f84f66fea9
140 Risk Score

Malware Insights

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

The sample is an OOXML file encrypted with a default password, indicating it's designed to hide its malicious content. It contains multiple OLE objects, specifically identified as Equation Editor objects, which are known exploit carriers. One of these objects, 'oleObject1.bin', exhibits an anomaly where an Equation Editor object carries a payload-like Ole10Native stream, strongly suggesting it's used to deliver a secondary exploit or payload.

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.