Xls.Downloader.Trojan-aa0b8f388d8573cd-aa0b8f388d8573cd-9950439-0 — Office (OOXML) / .XLSX malware analysis

Static analysis result for SHA-256 8c9edcf241f42202…

MALICIOUS

Office (OOXML) / .XLSX

840.5 KB Created: 2022-05-16 17:34:45 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-06-09
MD5: 95a0cdd27f88dc298400e8eef121a8e4 SHA-1: 8aaca12d38d4a70c4ab643846a07b4c184fdcd82 SHA-256: 8c9edcf241f42202e0be566ca9631f8836849b57328329e36166f9cfe6be312f
160 Risk Score

Malware Insights

Xls.Downloader.Trojan-aa0b8f388d8573cd-aa0b8f388d8573cd-9950439-0 · confidence 95%

MITRE ATT&CK
T1204.002 Malicious File

The critical ClamAV detection and high-severity heuristics indicate this XLSX file contains an embedded Equation Editor OLE object that carries a payload. This payload is likely responsible for downloading and executing a secondary stage, as suggested by the 'Downloader' component of the ClamAV detection name. The embedded OLE object and its anomalous Ole10Native stream are key indicators of this exploit.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/9dw.YhESBx 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
e1e1afd060241563a5c020b728f5facfc85fca88e1b4946fcdd8846ae51d181f		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/9dw.YhESBx 1013248 bytes
ooxml_oleobject_00_ole10native_00.bin
ba59acb06457d587cf2d13872d431af739d07ccea62f9d6bf9d8e064ff227c59		 ole-package OOXML xl/embeddings/9dw.YhESBx Ole10Native stream: ole10nATiVE 1002593 bytes
emf_00.emf
38f17a599ac5d645df3840bbb401710ef81573a747da20abbfc1b7d9a9273b58		 ooxml-emf OOXML EMF part: xl/media/image1.emf 169096 bytes

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