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

Static analysis result for SHA-256 4b9bd9441358e7d4…

MALICIOUS

Office (OOXML) / .XLSX

668.2 KB Created: 2023-07-26 19:45:53 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2023-10-26
MD5: fe744883775594a66fbf3d850732fec0 SHA-1: 7cbbe8ba0e27b1c4633cc976dc233aa58464502c SHA-256: 4b9bd9441358e7d427d98b2fbe55d90ed85ad0bee61d0b2874f5664f8b65333c
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 Equation Editor object. High-severity heuristics indicate that this Equation Editor object carries a payload-like Ole10Native stream with an anomalous size, strongly suggesting exploitation of a vulnerability such as CVE-2017-11882. The embedded object is likely used to download and execute a second-stage payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/iYCO.OVFhS 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
2a6f7daf53b799de066a66d21b7fac2da528d72c8103cb219ad37969c79219d8		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/iYCO.OVFhS 966656 bytes
ooxml_oleobject_00_ole10native_00.bin
6de99ac53bc572231393fbf0b6df9ec6b16bceeb263afb4e2ab222fca96b66b8		 ole-package OOXML xl/embeddings/iYCO.OVFhS Ole10Native stream: olE10natIve 956545 bytes

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