Malicious Office (OOXML) / .XLSM — malware analysis report

Static analysis result for SHA-256 e2092adac73f8bb4…

MALICIOUS

Office (OOXML) / .XLSM

86.1 KB Created: 2020-05-30 19:21:49 UTC Authoring application: Microsoft Excel 14.0300
MD5: 425b80a2697d1a246f859dc207db7f91 SHA-1: ca0050c6b84127ccedf417ea82f6215687779a39 SHA-256: e2092adac73f8bb456547a61815662e5ec01016ba9a7b0d2ab53eb316c9f4c5a
108 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Service Execution: Visual Basic T1204.002 Malicious File: User Execution: Malicious File T1105 Ingress Tool Transfer

This XLSM file contains Excel 4.0 macros, a technique commonly used to bypass VBA-focused security controls. The macros utilize dangerous functions like CALL and FORMULA to download a payload from the URL https://urleddrug.at/3/slk.dll and execute it using regsvr32.exe or rundll32.exe. The presence of hidden sheets further suggests an attempt to conceal malicious activity.

Heuristics 4

  • Dangerous XLM formula APIs: RUN, FORMULA, CALL, HALT critical OOXML_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet uses formula APIs that call directly into Win32 (=CALL/=EXEC/=REGISTER/=FORMULA). These are the primitives used to download payloads, write files, and start processes from an XLM macro without invoking VBA.
  • Excel 4.0 macro sheet (1 sheet(s)) high 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.
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 17 hidden sheet(s) — hidden sheets are commonly used to conceal macro code, staging data, or intermediate payload construction
  • 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://urleddrug.at/3/slk.dll

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
74de52f91d9300777923cc5fbb9b143f96cd631ea5419e3377a623b4578bc4d3		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 64151 bytes

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