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

Static analysis result for SHA-256 2133f0ac020b4a6c…

MALICIOUS

Office (OOXML) / .XLSX

680.9 KB Created: 2023-08-03 11:34:29 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2023-09-20
MD5: 1237c14b97130e66bf3808f73c21b775 SHA-1: 747586893298a758510d2b3ac1444eaaef415b9c SHA-256: 2133f0ac020b4a6cb5299e2d4f3d9b019406ac5b4603a99b2cafb71635cda1bc
100 Risk Score

Malware Insights

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

The sample is an Office document containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. High-severity heuristics indicate that this Equation Editor object carries a payload-like Ole10Native stream with an anomalous header and a significantly larger declared inner size than the actual stream size, strongly suggesting exploitation of a vulnerability within the Equation Editor component. This mechanism is commonly used to execute arbitrary code.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/8Jr.lpG 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
5a23789dbf4de96578353d63edfda5c3bbc529f089e32ce155ac609b3b805da6		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/8Jr.lpG 998400 bytes
ooxml_oleobject_00_ole10native_00.bin
1c5be3e216880dd972b26c97677eba4a8b64b98eb5be5b7a5abf08f1609f09a9		 ole-package OOXML xl/embeddings/8Jr.lpG Ole10Native stream: oLE10NAtiVe 987934 bytes

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