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

Static analysis result for SHA-256 202b890db0b579d3…

MALICIOUS

Office (OOXML) / .XLSX

822.7 KB Created: 2022-05-16 17:34:45 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2023-07-08
MD5: 6792a83bfb9841be2d9b7078197b02ef SHA-1: f1cc4ae5dfb7d313a6d3d7d40671472d30f027e6 SHA-256: 202b890db0b579d3ef5c3da64a38eaccafe80eb3b43a352a2b64c62dc3a01c1b
160 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious File T1559 Component Object Model Hijacking T1559.001 Component Object Model Hijacking: Component Object Model Hijacking

The sample is an Excel file containing an embedded OLE object identified as an Equation Editor. 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. This strongly suggests the object is being used to deliver a secondary malicious payload, consistent with a downloader or exploit dropper.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/rq4Xh.od contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • ClamAV: Xls.Downloader.Trojan-aa0b8f388d8573cd-aa0b8f388d8573cd-9950439-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Trojan-aa0b8f388d8573cd-aa0b8f388d8573cd-9950439-0
  • 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
ooxml_oleobject_00.bin
6b71c57c1692bf22ad3ba1450c41aa254b3dbb8242f8fee4c896604f5ceefd91		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/rq4Xh.od 991744 bytes
ooxml_oleobject_00_ole10native_00.bin
e5f31c34853ee44aaf3a8e3d6913d1561dbd6ce4fec5385612d708e94cd97083		 ole-package OOXML xl/embeddings/rq4Xh.od Ole10Native stream: olE10nAtIve 981170 bytes
emf_00.emf
38f17a599ac5d645df3840bbb401710ef81573a747da20abbfc1b7d9a9273b58		 ooxml-emf OOXML EMF part: xl/media/image1.emf 169096 bytes

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