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

Static analysis result for SHA-256 5b45d5f627e2b91e…

MALICIOUS

Office (OOXML) / .XLSX

863.7 KB Created: 2021-08-09 02:12:21 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2022-09-16
MD5: bfcbfd52021ce5f325dbebcdba9e1201 SHA-1: bc7e028063cf7b68e1a165b4c5482ce52b91aec3 SHA-256: 5b45d5f627e2b91e149c70d19f393682932f207adad22973e6a6f590dcf05ad5
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1559.001 Component Object Model Hijacking

The sample is an Office Open XML spreadsheet containing an embedded OLE object, specifically identified as a vulnerable Equation Editor component. Heuristics indicate this object carries a payload-like Ole10Native stream, strongly suggesting exploitation of CVE-2018-0798 for client-side execution. The embedded object's path is noted as a primary indicator.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/xn.Cg7 contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • CVE-2018-0798 — anomalous Equation Editor native stream high CVE likely CVE_2018_0798_EQUATION_NATIVE_ANOMALY
    Embedded Equation Editor OLE data contains anomalous native stream bytes consistent with a CVE-2018-0798-style Equation Editor exploit. This is treated as likely CVE evidence because the Equation object is malformed and payload-like, but it does not match the exact public matrix-overflow byte signature.
  • 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
590e1816cc96559841629ca31164081bd8eb5d02e2c9bb24d2eb1db395191285		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/xn.Cg7 1191424 bytes
ooxml_oleobject_00_ole10native_00.bin
70d351ba8c816531bb1a0a69132983f5b2a4355c886c0befabbbc92741035105		 ole-package OOXML xl/embeddings/xn.Cg7 Ole10Native stream: OLE10NaTiVe 1179458 bytes

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