Qbot Office (OOXML) / .XLSX malware analysis — malicious · f2afc148973efeb8

MALICIOUS

Office (OOXML) / .XLSX

1.31 MB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-05-27

MD5: bbfecf2dd5a5f46ba24096a72f73c68a SHA-1: 22ec955f426b00df1e3741b5a3e06cce8a4ecb7d SHA-256: f2afc148973efeb8571d0953bc6d84dbe9352c6e9534c2e6571ea632d9faa1d8

262 Risk Score

Malware Insights

Qbot · confidence 95%

MITRE ATT&CK

T1059.005 Service Execution: Visual Basic T1204.002 Malicious File: User Execution: Malicious File T1059.001 Command and Scripting Interpreter: PowerShell T1059.003 Command and Scripting Interpreter: Windows Command Shell T1105 Ingress Tool Transfer

This XLSX file contains Excel 4.0 macros, detected by multiple critical heuristics. The macros utilize dangerous functions like REGISTER, EXEC, and GOTO to download and execute a second-stage payload. The embedded URLs and the reconstructed URL 'http://urlmonurl/downloadtofilea' strongly suggest a downloader functionality, consistent with the Qbot family identified by ClamAV. The macros also attempt to establish persistence by writing to the registry, as indicated by the use of REGISTER and the presence of registry-related strings.

Heuristics 6

Excel 4.0 macro sheet (6 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: GOTO, REGISTER, EXEC, 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.Qbot-b760f03263b7c21b-9950248-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Xls.Downloader.Qbot-b760f03263b7c21b-9950248-0
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 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
- http://schemas.microsoft.com/office/spreadsheetml/2014/revision
- http://schemas.microsoft.com/office/spreadsheetml/2015/revision2
- http://schemas.microsoft.com/office/spreadsheetml/2016/revision3
- http://schemas.microsoft.com/office/spreadsheetml/2016/revision6

Extracted artifacts 6

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_sheet_00.xml` `a7e3733b1363628adf7f51c156b74365950f080ba7eb4fb4a9f0561e8e860639`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.xml	1955 bytes
`xlm_sheet_01.xml` `b44fde067371b12dff23c94bd54325d79e5ed12a642515c6814a3d3bcee92f70`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet2.xml	1647 bytes
`xlm_sheet_02.xml` `df5dcaca6a4f73d2d3be21c15544097e49bc8f2c3942e49075fe6111bf9a9c06`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet3.xml	1522 bytes
`xlm_sheet_03.xml` `f4c2e30869426e0361f025e6392fc8e2e068bedc236f165352f6b1b990b6a40f`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet4.xml	1521 bytes
`xlm_sheet_04.xml` `d6235f8a5edd43e99b29c95384f3bbc577ea8a7c083dff4fdf82519e38769532`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet5.xml	1523 bytes
`xlm_sheet_05.xml` `c04e216d19774237836ba44a0779b3ff7986a81d2f6ddcc95cfb7b0cf99d3883`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet6.xml	1632 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 5 shell/COM execution token(s).

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