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

Static analysis result for SHA-256 8dcfe90117138a04…

MALICIOUS

Office (OLE) / .XLSX

2.49 MB
MD5: 1b3c67d703ca79d677c1b156f3c0a9d5 SHA-1: 38009241033cd93dbe3c6edf92c8a04ba467bf96 SHA-256: 8dcfe90117138a044f1cf95fd4b55c4c736d1e8507307ea53e8ca8d9d4c2d08c
180 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1566 Phishing T1204.001 Malicious Link: Malicious Link T1566.001 Phishing: Spearphishing Attachment

The sample is an encrypted OOXML file that contains an embedded Equation Editor OLE object. High-confidence heuristics indicate that this object is anomalous and likely carries a malicious payload, specifically exploiting CVE-2018-0798. The encrypted nature of the document prevents direct analysis of its content, but the presence and characteristics of the Equation Editor exploit strongly suggest its purpose is to execute arbitrary code.

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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