Qbot — Office (OOXML) / .XLSM malware analysis

Static analysis result for SHA-256 a90caac100eebb74…

MALICIOUS

Office (OOXML) / .XLSM

166.6 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 14.0300
MD5: c183eaa5141e4d2d4bc699d1a97aee50 SHA-1: 2c22cae2e1ad03a7ff4495d61eb96d6415d9a169 SHA-256: a90caac100eebb74742349dab96b733bb86f8f08f5060aabf8db893fa9ea7c5e
260 Risk Score

Malware Insights

Qbot · confidence 95%

MITRE ATT&CK
T1059.005 Service Execution: Visual Basic T1204.002 Malicious File: User Execution T1059.001 Command and Scripting Interpreter: PowerShell T1105 Ingress Tool Transfer

The file is an Excel macro-enabled spreadsheet (XLSM) containing Excel 4.0 macros. Critical heuristics indicate the use of dangerous XLM functions like CALL and EXEC, which are commonly used to download and execute payloads. The presence of Auto_Open and the ClamAV detection as 'Xls.Downloader.Qbot' strongly suggest a Qbot downloader variant. The extracted URLs are likely the sources for the second-stage payload.

Heuristics 6

  • Excel 4.0 macro sheet (4 sheet(s)) critical OOXML_XLM_MACROSHEET
    Spreadsheet contains an Excel 4.0 (XLM) macro sheet — XLM was a major Office malware vector during 2020-2022 and evaded many VBA-focused controls before Microsoft tightened XLM defaults. Even legitimate XLM use is rare in modern workbooks.
  • Excel 4.0 Auto_Open defined name critical OOXML_XLM_AUTOOPEN_DEFINEDNAME
    Workbook defines _xlnm.Auto_Open or _xlnm.Auto_Close while containing an XLM macro sheet. This is the OOXML/XLSB auto-execution shape for Excel 4.0 macros.
  • Dangerous XLM formula APIs: EXEC, FORMULA, CALL, HALT critical OOXML_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet uses formula APIs that call directly into Win32 (=CALL/=EXEC/=REGISTER/=FORMULA). These are the primitives used to download payloads, write files, and start processes from an XLM macro without invoking VBA.
  • ClamAV: Xls.Downloader.Qbot0421-9856653-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Qbot0421-9856653-0
  • Suspicious extracted artifact medium EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://yohsinsolutions.com/0QeH3HFbNyY/kk.html
    • https://gtec24.com/0mqp0yN6/kk.html
    • http://ns.adobe.com/xap/1.0/
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/photoshop/1.0/
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/sType/ResourceEvent#
    • http://ns.adobe.com/xap/1.0/sType/ResourceRef#
    • http://schemas.openxmlformats.org/spreadsheetml/2006/main
    • http://schemas.microsoft.com/office/excel/2006/main
    • http://schemas.openxmlformats.org/officeDocument/2006/relationships
    • http://schemas.openxmlformats.org/markup-compatibility/2006
    • http://schemas.microsoft.com/office/spreadsheetml/2009/9/ac

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
3053dafa2d3f987ce513cbeee21a23bb155656d1a3bacf27e3c9fd23a98df2cd		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet3.xml 1245 bytes
xlm_sheet_01.xml
7c70a733295093fa9be986f7921d4989b1ff5b1c9e7d7c0416a4b8d6aa837808		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 204903 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 shell/COM execution token(s).
xlm_sheet_02.xml
6cb3ab47226c206f666f8830fc35f10e422712c9d53bd66c647d57a05f0b41bc		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet2.xml 4485 bytes
xlm_sheet_03.xml
95eb9ac669583f7114c029725ae2ac1b158fd43ff181b1370db5057cd2dc1558		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet4.xml 1082 bytes

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