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

Static analysis result for SHA-256 828107b686c52c28…

MALICIOUS

Office (OOXML) / .XLSX

631.5 KB Created: 2010-06-04 08:55:28 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2023-08-22
MD5: 926ad1b04f5753e749f0e024cf6f61a6 SHA-1: 24cc1d23256627e8289c2db8b44d6084f96bdc87 SHA-256: 828107b686c52c28cd01c0bf81e55d7aaf8cf8953c775380b6cd3a98c890ed9a
100 Risk Score

Malware Insights

MITRE ATT&CK
T1559.001 Component Object Model Hijacking T1204.002 Malicious File

The sample is an Office document containing an embedded OLE object, specifically identified as a vulnerable Equation Editor object. This object carries a payload-like Ole10Native stream, indicating it's designed to execute malicious code. The large declared inner size compared to the stream size suggests potential obfuscation or a packed payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/tmFgM5X.ht 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
75a9025e720bf4b97461a0901397b34b0f72a47d82f43270e91c91e35b3eb829		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/tmFgM5X.ht 864256 bytes
ooxml_oleobject_00_ole10native_00.bin
6b2c5dd66400fe4e330833fff6b1f4c3c583a2f88dd0a9e98d669cc91ef62402		 ole-package OOXML xl/embeddings/tmFgM5X.ht Ole10Native stream: Ole10NAtivE 854815 bytes

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