Qbot — Office (OOXML) / .XLSX malware analysis

Static analysis result for SHA-256 6fb8923c1c1342a7…

MALICIOUS

Office (OOXML) / .XLSX

333.2 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-02-28
MD5: 6134ef8f900948e00c23e987422d8863 SHA-1: 141341dae270cafeb071d7f6aaa14a7fa591ac63 SHA-256: 6fb8923c1c1342a7e4f0df34c4d7260309eb3cb94dc181569085c331c9c2f68f
180 Risk Score

Malware Insights

Qbot · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file contains Excel 4.0 macros, identified by the OOXML_XLM_MACROSHEET heuristic. These macros are designed to reassemble a payload, as indicated by OOXML_XLM_REASSEMBLED_PAYLOAD, and download it from a URL. The ClamAV detection name 'Xls.Downloader.Qbot-aa2a2a3fd5f4342a-9950245-0' strongly suggests the Qbot family. The script explicitly constructs URLs such as 'http://a' and IP addresses like '146.19.170.74/' which are likely C2 servers for downloading the next stage.

Heuristics 3

  • Excel 4.0 macro sheet (13 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. The macro sheet is stored as XLSB/BIFF12 binary content, which many XML-only OOXML scanners miss.
  • XLM payload reassembled from CHAR()/split formulas critical OOXML_XLM_REASSEMBLED_PAYLOAD
    An Excel 4.0 macro sheet builds its payload inside the formula token stream by concatenating per-character CHAR() calls and string fragments, so no WinAPI name, shell command, or URL is ever contiguous in the .bin for a literal-bytes scan to find. Reassembling the formulas recovered download/execute API names, LOLBin commands (regsvr32/rundll32/mshta/wmic/powershell), or a payload URL — the de-obfuscated download-and-run kill chain.
  • ClamAV: Xls.Downloader.Qbot-aa2a2a3fd5f4342a-9950245-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Qbot-aa2a2a3fd5f4342a-9950245-0

Extracted artifacts 13

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.bin
5fb5a9e6ec1dacc189efcc6a68093d9b5c376b223dcb27f862984427d2aac0e2
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.bin 363 bytes
xlm_sheet_01.bin
9240857c038d474bda71d25a9bdc03e9bd845927780c5c30c8ad2d215fc30299
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet2.bin 918 bytes
xlm_sheet_02.bin
37305deb6977106275d104f5826c9a1ae694574dcf133bc8f0a88e69659fa5d9
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.bin 2263 bytes
xlm_sheet_03.bin
d795a42e7dfb9f3b384d1e5d47d879eee778b9da4bf4a945b3272471187b3422
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet3.bin 1703 bytes
xlm_sheet_04.bin
93c463343ef7f1e9e791647d561f007c38659ae4a327b3ebb864f048f16a58f6
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet4.bin 659 bytes
xlm_sheet_05.bin
4d4dd95373ceffcdeae0a74dfa09b90bd3ce229ab64dd70c7fe0f05e5b469bbd
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet5.bin 648 bytes
xlm_sheet_06.bin
8d957f41705fc5da60f409cd3c460bdb601935e6214bf78485f23a85cb252024
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet6.bin 622 bytes
xlm_sheet_07.bin
000bc8d70715fdc1e9f90bbf8ea8d827eb7d942c3f16b2c5b6d16539d6622ba7
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet7.bin 446 bytes
xlm_sheet_08.bin
104ea4dd6393a2e7568a3476bef8861dc03f02ff70847c1579759679f5b37241
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.bin 843 bytes
xlm_sheet_09.bin
617d9277b8cae5e22b22f75d36f1c1410a208c497dfd9b1fc50732ce8b8e39ba
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet8.bin 423 bytes
xlm_sheet_10.bin
fe57f943858a8919ed6e91709a3b6f572e0ddbcba21b32c8fbf3c96821baa7a0
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet3.bin 748 bytes
xlm_sheet_11.bin
93ba72b98161dad073a1ddc9f87bed6380b6a369d49aed308df35146fe953084
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet4.bin 748 bytes
xlm_sheet_12.bin
2bd138650fa507a83c5a96a8b7ece29759f24ed721eaf50eae3ada328413aacb
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet9.bin 423 bytes