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

Static analysis result for SHA-256 b6558bfab4fdd4bb…

MALICIOUS

Office (OOXML) / .XLSX

733.7 KB Created: 2023-07-26 19:45:53 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-10-10
MD5: a8606bec9c6bdde5ba554f17478f3e71 SHA-1: 6ea4ef16a5d2f54ec973482ee74ef8605669e02e SHA-256: b6558bfab4fdd4bbb616145a27d59f9ecbe5ac7d95e2dcd11902ecab63908a7d
100 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious File T1559 Component Object Model Hijacking

The file contains an embedded OLE object, specifically identified as a Microsoft Equation Editor object. This object exhibits an anomaly where the Ole10Native stream appears to carry a payload, indicated by an impossible header and a significant size discrepancy. This strongly suggests the Equation Editor is being used as a vector to exploit a known vulnerability for delivering a secondary malicious payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/M3J8u4X0w.YaS contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • Equation Editor object carries payload-like Ole10Native stream high OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY
    Embedded OLE object declares the Equation Editor CLSID but stores a large high-entropy Ole10Native stream with malformed package sizing. This is an exploit-shaped Equation/OLE payload container seen in malicious OOXML samples. It is not assigned to a specific CVE unless the MTEF/Equation Native primitive also matches.
  • Embedded OLE object medium OOXML_OLE_OBJECT
    Document contains an embedded OLE object

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
ooxml_oleobject_00.bin
989b6c8b9e6812006d43c7e0c8df7236d6285e31323dcb7ae9f0c0957aa700d4		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/M3J8u4X0w.YaS 1012736 bytes
ooxml_oleobject_00_ole10native_00.bin
1ce00c26551eae365bb147c00a29994068ea3a15679559b7abcaab26275b30ab		 ole-package OOXML xl/embeddings/M3J8u4X0w.YaS Ole10Native stream: oLe10NatIvE 1002244 bytes

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