Qbot Office (OOXML) / .XLSX malware analysis — malicious · 3dc504b828229c74

MALICIOUS

Office (OOXML) / .XLSX

1.31 MB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-05-26

MD5: 908976af9b8a9189122832120dfb774d SHA-1: 91a2cf1580649b6d0375b89792c96efa1a0868e5 SHA-256: 3dc504b828229c746d13dfa6641a8bcf13be87c147fc347a4630e336dc9167a2

262 Risk Score

Malware Insights

Qbot · confidence 95%

MITRE ATT&CK

T1059.005 Service Execution: Visual Basic T1204.002 Malicious Link: Malicious File T1059.001 Command and Scripting Interpreter: PowerShell T1059.003 Command and Scripting Interpreter: Windows Command Shell T1059.006 Command and Scripting Interpreter: Python

The sample is an Excel file containing Excel 4.0 macros, identified by multiple critical heuristics. These macros utilize dangerous functions like GOTO, REGISTER, and EXEC, which are commonly used to download and execute malicious payloads. The ClamAV detection explicitly names this as a Qbot downloader. The embedded URLs in the DOC BODY section are likely sources for the second-stage payload.

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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