Qbot — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 a9c1ebf3b29193a5…

MALICIOUS

Office (OLE) / .XLS

129.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel
MD5: c1c4dd437816c84a61d95b56bcf8b306 SHA-1: 660cd6beb04fad686465fe11a42c6f84b7e2a21c SHA-256: a9c1ebf3b29193a58b45e557d94cfe8d5b306e94c03fc4051d2d8e4a302160ea
262 Risk Score

Malware Insights

Qbot · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File

The file contains Excel 4.0 macros, specifically an Auto_Open function that executes dangerous API calls. The macro reconstructs and executes URLs to download a second-stage payload. The ClamAV detection and the nature of the macro strongly indicate a Qbot downloader. The reconstructed URLs are: "https://greenflag.esp.br/yuINdRbM/tiynh.html", "https://noithat117.vn/TSh7GBeIR/tiynh.html", and "https://playsis.com.br/qJSL1BN5V/tiynh.html".

Heuristics 6

  • Excel 4.0 Auto_Open defined name critical OLE_XLM_AUTOOPEN_DEFINEDNAME
    oletools recovered an Auto_Open / Auto_Close entry from an Excel 4.0 macro sheet. The raw BIFF name can be tokenized or partially opaque to byte-string checks, but the recovered macro listing confirms the workbook has an XLM auto-execution entry.
  • XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
  • URL reconstructed from XLM cell array (3 URLs) critical OLE_XLM_CELL_ARRAY_URL
    Excel 4.0 macro sheet stages its payload URL across the BIFF8 Shared String Table (one quoted-char SST entry concatenated with & at runtime) or across individual numeric cells (one ASCII charcode per cell). The reconstructed URL is invisible to literal-bytes URL extraction because it is never contiguous in the workbook stream. URLs were recovered by walking the BIFF8 record stream and decoding SST entries plus LABELSST/RK/NUMBER cells.
  • ClamAV: Doc.Downloader.Qbot12212-9916031-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Qbot12212-9916031-0
  • Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN
    Workbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.
  • 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://greenflag.esp.br/yuINdRbM/tiynh.html
    • https://noithat117.vn/TSh7GBeIR/tiynh.html
    • https://playsis.com.br/qJSL1BN5V/tiynh.html

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
62f50c897842d22b8695eb5150012b1b8c93ededf323ca658f70248c3cc83148		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 10933 bytes

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