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

Static analysis result for SHA-256 32191c55ba487fff…

MALICIOUS

Office (OLE) / .XLSX

1.22 MB
MD5: 36a45d2a7f17103ea27d6d3c7f07f6e7 SHA-1: e4fd69343138a7aa48b4956cd1b25c03cf30b508 SHA-256: 32191c55ba487fff6e0c8daa7cc0e75143d8bb8ef55f6e6a5a0cfed8d4a5ee92
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File T1559.001 Component Object Model

The sample is an encrypted OOXML file that contains embedded OLE objects, specifically identified as Equation Editor objects. The presence of an 'Ole10Native' stream within the Equation Editor object, coupled with an anomalous header and a significant discrepancy between declared and actual stream size, strongly indicates that it is being used as an exploit carrier. This points to a likely attack pattern involving the Equation Editor vulnerability (CVE-2017-11882) to execute a secondary 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.