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

Static analysis result for SHA-256 9f5bfb9a4797022b…

MALICIOUS

Office (OOXML) / .XLSX

597.6 KB Created: 2023-07-26 19:45:53 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-09-15
MD5: 2a815c0fcafa52cd860377ad26c8da39 SHA-1: 744c612d9962731d6d29888db17726f33f0f4165 SHA-256: 9f5bfb9a4797022bd537630b6113bccd9749482ef236d21a31763389f39ab6d7
100 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.001 Malicious Link

The file is an Excel document containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. Heuristics indicate that this Equation Editor object carries a payload-like Ole10Native stream with an anomalous size and entropy, strongly suggesting it's being used to exploit a known vulnerability (e.g., CVE-2017-11882) to execute arbitrary code. The embedded object's filename and stream name are noted as potential IOCs.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/QocFNL1D.wG 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
b768314c17ce60d3f7d8369f927630db305a516b562658313355fb3e9fdd11e6		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/QocFNL1D.wG 821248 bytes
ooxml_oleobject_00_ole10native_00.bin
a2f6612d3202c3bc20a962d39be18fa0572c190e227b16c9e9082a6aebd93f43		 ole-package OOXML xl/embeddings/QocFNL1D.wG Ole10Native stream: OlE10nAtIVE 812509 bytes

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