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

Static analysis result for SHA-256 2eec4a04a8c54749…

MALICIOUS

Office (OOXML) / .XLSX

763.0 KB Created: 2022-05-16 17:34:45 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2023-04-14
MD5: 46b9c89eb80bc7fab6692eb7cd14cd9a SHA-1: eef09b6379f470f7806ba02499de2d4153e5dee4 SHA-256: 2eec4a04a8c54749db08aed19994e6e586987007388f71e4521d107cb9d1f901
160 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 an Equation Editor object. High-severity heuristics indicate that this Equation Editor object carries a payload-like Ole10Native stream with an anomalous header and size discrepancy, strongly suggesting exploitation. ClamAV detection confirms this as a downloader trojan. The presence of these indicators points to a malicious document designed to exploit the Equation Editor vulnerability to download and execute a secondary payload.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/lApeNdiKg.fFi 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
6a158c663b789bca967459e570a58ecbd26fa3020f73026dd5d1eaa887f7c591		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/lApeNdiKg.fFi 899072 bytes
ooxml_oleobject_00_ole10native_00.bin
53a5e6843c45a9c12b63e4471cf1a23a233658517a31e5709da510c42ab02a00		 ole-package OOXML xl/embeddings/lApeNdiKg.fFi Ole10Native stream: OLE10NaTivE 889540 bytes
emf_00.emf
38f17a599ac5d645df3840bbb401710ef81573a747da20abbfc1b7d9a9273b58		 ooxml-emf OOXML EMF part: xl/media/image1.emf 169096 bytes

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