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

Static analysis result for SHA-256 a5dd8c8fdf89d052…

MALICIOUS

Office (OLE) / .XLSX

2.07 MB
MD5: 095bc46d2f5a2406f01886967498636b SHA-1: 09890acf53d0bd3881b157ff6c91d8b2e71dc25e SHA-256: a5dd8c8fdf89d052d78f1b53b89b0c1936289c006cdb41346b3b935527934c48
180 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1566 Phishing T1204.002 Malicious File T1059 Command and Scripting Interpreter

The file is an encrypted Office XLSX document that contains an embedded Equation Editor OLE object. Heuristics indicate this object is anomalous and likely carries a malicious payload, exploiting CVE-2018-0798. The encryption and the nature of the embedded object suggest a delivery mechanism for a second-stage exploit or malware.

Heuristics 5

  • 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.
  • CVE-2018-0798 — anomalous Equation Editor native stream high CVE likely CVE_2018_0798_EQUATION_NATIVE_ANOMALY
    Default-encrypted OOXML contains embedded Equation Editor data with anomalous native stream bytes consistent with a CVE-2018-0798-style exploit. This is treated as likely CVE evidence because the Equation object is malformed and payload-like.
  • 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.

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