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

Static analysis result for SHA-256 ef29136a51d96f92…

MALICIOUS

Office (OOXML) / .XLSX

593.1 KB Created: 2023-07-26 19:45:53 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-08-16
MD5: 8e1989dbdbce50938e7e033ee1d1db1d SHA-1: 819e38ffff3cd9852c410d88a6e6821d4aa41db0 SHA-256: ef29136a51d96f92049b3870589f9f53e446317d67238fbaedb118e7f5327ed7
100 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.001 User Execution: Malicious Link T1059.003 Windows Command Shell T1059.001 PowerShell

The file is an Office Open XML spreadsheet containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. High-severity heuristics indicate that this Equation Editor object carries a payload-like Ole10Native stream with an anomalous header, suggesting it's designed to exploit a vulnerability. This is a common delivery mechanism for malware, often leading to the execution of a second-stage payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/HXthET920.M9 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
b4becb20c1cd0b904abbe8c367ee7e93427515ca51c14a8be2a324f9059df4f6		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/HXthET920.M9 856064 bytes
ooxml_oleobject_00_ole10native_00.bin
7155f2efbfc9d2f290ad47f79e4c6a513ab6b5a988d794244cfbd206076cbbba		 ole-package OOXML xl/embeddings/HXthET920.M9 Ole10Native stream: oLE10NATIVE 846507 bytes

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