SquirrelWaffle — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 20a6da8e1c73e79b…

MALICIOUS

Office (OLE) / .XLS

263.0 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel
MD5: 6ce22ba6bf8f09805d88f40d26cb1fb6 SHA-1: c30c9ab0d84dbcabd833f4a1c594b09352e80379 SHA-256: 20a6da8e1c73e79b04ea1ec5a169b7635b2eac9c55c7d928e3278c86ce89ced6
242 Risk Score

Malware Insights

SquirrelWaffle · confidence 95%

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

The file contains Excel 4.0 macros, specifically an Auto_Open macro, which is a strong indicator of malicious intent. The macros are designed to download and execute a payload from one of the provided URLs. The ClamAV signature 'Xls.Downloader.SquirrelWaffle20921-9895790-0' further supports the SquirrelWaffle family attribution. The reconstructed URL 'http://the.earth.li/~sgstham/putty/0./w/puttyxe.C=()' is also suspicious.

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.
  • 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: Xls.Downloader.SquirrelWaffle20921-9895790-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.SquirrelWaffle20921-9895790-0
  • Reference to ShellExecute API high SC_STR_SHELLEXEC
    Reference to ShellExecute API
  • 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://elitekhatsacco.co.ke/s6OkhAya/day.html
    • https://sukmabali.com/rwZiioLFaG/day.html
    • https://lfzombiegames.com/P8BJd4OW/day.html

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
6359b46e6d514cb3efc6a0d7784e7400aac3178f41b63e68c532798d02de0399		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 10821 bytes

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