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

Static analysis result for SHA-256 fe25c3089f208c11…

MALICIOUS

Office (OOXML) / .XLSX

688.7 KB Created: 2021-09-22 12:07:42 UTC Authoring application: Microsoft Excel 12.0000
MD5: 5fde25122e741d003219a93eb66d357f SHA-1: c77d66489b42fd4cd0fdcd5d6fdfa8833dec5b80 SHA-256: fe25c3089f208c115146259347cb035fa4fe898de213dec78f0bc0f58b73275c
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1559 Component Object Model Hijacking

The file contains an embedded OLE object, specifically identified as a Microsoft Equation Editor object. High-severity heuristics indicate that this object is anomalous and carries a payload, strongly suggesting exploitation of CVE-2018-0798. This technique is commonly used to deliver second-stage malware. No document body or scripts were extracted, but the presence of the malicious Equation Editor object is sufficient evidence for this assessment.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/XKEqQ.96t 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
d7ae13b3b72e55099879827cce7ecff3f291cc940329f1c97032ec340eb1fa98		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/XKEqQ.96t 968704 bytes
ooxml_oleobject_00_ole10native_00.bin
3ebd8e10b5a3214bea3c8aa55534de8f8427c661f5f0744585e38f8a147c3b6c		 ole-package OOXML xl/embeddings/XKEqQ.96t Ole10Native stream: olE10NAtiVE 958965 bytes

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