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

Static analysis result for SHA-256 765255819cdb12a6…

MALICIOUS

Office (OOXML) / .XLSX

632.7 KB Created: 2023-08-03 11:34:29 UTC Authoring application: Microsoft Excel 16.0300
MD5: 38b0395ec403b5b1225ee6314f22b761 SHA-1: 0282f2f27e29ed5ab34bbde3b454175e97d55921 SHA-256: 765255819cdb12a6e19ec36b59cac565620212b2f595ad8a9c47cb96ac649975
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The sample is an Excel document containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. Heuristics indicate that this object carries a payload-like stream with an anomalous header, suggesting it's designed to exploit a vulnerability. The presence of a NOP sled further supports the exploitation of a client execution vulnerability, likely delivered via spearphishing attachment.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/jhXX.m3 contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • NOP sled detected high SC_NOP_SLED
    Found 20+ consecutive 0x90 bytes
  • 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
f2f9185cf02d027933863ff40ed100a126e9ed21b802e995af035d75e5c4a67c		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/jhXX.m3 902144 bytes
ooxml_oleobject_00_ole10native_00.bin
fdc1f7b52fe1cd7f25220793401073dd14dadea89c1e719b6d2b05a369a59993		 ole-package OOXML xl/embeddings/jhXX.m3 Ole10Native stream: oLE10nativE 892861 bytes

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