SquirrelWaffle — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 2e92647a2100b612…

MALICIOUS

Office (OLE) / .XLS

263.0 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2021-09-25
MD5: a4a5a716ba5413b0e58daf24ad20828a SHA-1: 3d8edfcf69a0dee026439f239cf1dd0d9cf2643b SHA-256: 2e92647a2100b6125b2261b7ac39557e59719cab558a7ed477f290cf21c1e94f
242 Risk Score

Malware Insights

SquirrelWaffle · confidence 95%

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

The sample is an Excel 4.0 spreadsheet containing an Auto_Open macro, which is a known technique for executing malicious code. The macro utilizes the ShellExecute API and references dangerous functions like RUN, indicating it's designed to download and execute a payload. ClamAV detection confirms this, identifying it as Xls.Downloader.SquirrelWaffle. The embedded URLs are likely the sources for the secondary payload.

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.
  • 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://cortinastelasytrazos.com/Yro6Atvj/sec.html
    • https://orquideavallenata.com/4jmDb0s9sg/sec.html
    • https://fundacionverdaderosheroes.com/gY0Op5Jkht/sec.html

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
125eeb65449215b38b4c93bcf67effc9a2990373b692ed6d0729f78b6e651f74		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 9167 bytes

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