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

Static analysis result for SHA-256 de6389e89062e049…

MALICIOUS

Office (OOXML) / .XLSX

624.4 KB Created: 2023-09-05 22:54:24 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2023-09-06
MD5: 6cb5d8bac7218a2c8d1d6b32c7926e13 SHA-1: 751a136fbfc381b9cf242e5a41abb475de044c0f SHA-256: de6389e89062e049423ef018612df0734b94dfd9d9a4f3880ca6b8ff0bbbc4cc
100 Risk Score

Malware Insights

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

The file is an Excel document containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. 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 known vulnerability like CVE-2017-11882. This technique is commonly 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/c4mE8.Nmid 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
6d27961c7d3895243ab502bf8642242450ed6cb7f226b8140dbe7b5c6f635642		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/c4mE8.Nmid 861184 bytes
ooxml_oleobject_00_ole10native_00.bin
a446c9d5cd01e5f4fe3e6218b538755230bb98be53a18aab92e58de28e7e8fb8		 ole-package OOXML xl/embeddings/c4mE8.Nmid Ole10Native stream: OLe10natIve 851703 bytes

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