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

Static analysis result for SHA-256 2a5a51774b2e9fd3…

MALICIOUS

Office (OOXML) / .XLSX

646.6 KB Created: 2023-07-26 19:45:53 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-08-17
MD5: af054e815ad17533732fcea59fb94c8b SHA-1: 8fddb27147a2ac235bec4c7a950ae5e58efebfce SHA-256: 2a5a51774b2e9fd318756aaa0901a3f00e78d7a8370363cc90bc96a4e8819ed4
100 Risk Score

Malware Insights

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

The sample is an OOXML file containing 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 header and size discrepancy, strongly suggesting exploitation of a vulnerability within the Equation Editor component. This is a common delivery mechanism for exploiting Equation Editor vulnerabilities to execute arbitrary code.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/WnVvTB.ew2iz 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
cfb1485a055d224b73ac81cfe8e4d2d096041932474cbc45b9ab99928cade6bc		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/WnVvTB.ew2iz 888320 bytes
ooxml_oleobject_00_ole10native_00.bin
51b8045af1b466754938efc84a8e9d7a604b1c13ea5a1b30f3f134c70281628c		 ole-package OOXML xl/embeddings/WnVvTB.ew2iz Ole10Native stream: OlE10naTIvE 878757 bytes

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