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

Static analysis result for SHA-256 8f1985ce2ebb7e7e…

MALICIOUS

Office (OOXML) / .XLSX

671.9 KB Created: 2023-08-03 11:34:29 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2023-10-02
MD5: fd633beb9dcb441c9b4b2f5dd7881ad4 SHA-1: e898026497170c9a2f60092999929cd3bb5cbda2 SHA-256: 8f1985ce2ebb7e7e9bd718b0827f6bd7e5e1a10cc4c8faf54e55c7711e881b69
100 Risk Score

Malware Insights

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

The XLSX file contains an embedded OLE object, specifically identified as a Equation Editor object. High-severity heuristics indicate that this Equation Editor object carries a payload-like Ole10Native stream with an anomalous size difference, strongly suggesting it's a dropper for a secondary exploit or payload. The presence of this embedded malicious object points to a spearphishing attachment attack vector.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/ay7B.Jo6Z5zR 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
242c680fcb1d8d62c2b7044e81fd49a1a38cf550fd2cd3d6570c939ced4ae344		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/ay7B.Jo6Z5zR 917504 bytes
ooxml_oleobject_00_ole10native_00.bin
23921f2dabfa7af57e6e5b6ec1270a2eda52f14b6c453dac9789ce218419e13f		 ole-package OOXML xl/embeddings/ay7B.Jo6Z5zR Ole10Native stream: Ole10NaTIVE 907869 bytes

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