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

Static analysis result for SHA-256 0ad234bb3f6d830c…

MALICIOUS

Office (OOXML) / .OLE

91.8 KB Created: 2020-05-14 14:41:48 UTC Authoring application: Microsoft Excel 14.0300
MD5: 2775e2b90b05b2899e83d063948cd1c9 SHA-1: 8329151a0fc42405fd70d743f0fd357c6b9d6a2f SHA-256: 0ad234bb3f6d830cfdb896b8f45b59b8790e72fd3b834242ab1a35a0a7eb21a0
210 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file contains Excel 4.0 macros, specifically utilizing the RUN and CALL functions to execute external code. The macros appear to be designed to download a payload from the URLs 'https://post-990094.at/3/prc.dll' or 'https://post-990094.at/3/prc'. The use of dangerous XLM formula APIs like RUN and CALL directly indicates an attempt to execute arbitrary code, likely a second-stage malware downloader.

Heuristics 6

  • Excel 4.0 macro sheet (1 sheet(s)) critical 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.
  • Excel 4.0 Auto_Open defined name critical OOXML_XLM_AUTOOPEN_DEFINEDNAME
    Workbook defines _xlnm.Auto_Open or _xlnm.Auto_Close while containing an XLM macro sheet. This is the OOXML/XLSB auto-execution shape for Excel 4.0 macros.
  • Dangerous XLM formula APIs: RUN, 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.
  • Suspicious extracted artifact medium EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 13 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://post-990094.at/3/prc.dll
    • https://post-990094.at/3/prc
    • http://schemas.openxmlformats.org/spreadsheetml/2006/main
    • http://schemas.microsoft.com/office/excel/2006/main
    • http://schemas.openxmlformats.org/officeDocument/2006/relationships
    • http://schemas.openxmlformats.org/markup-compatibility/2006
    • http://schemas.microsoft.com/office/spreadsheetml/2009/9/ac

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
bef2159e9b2d70b96d090a9d5a07e979ca6add5229c60c702e34ef96b6102a5f		 xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 52136 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 shell/COM execution token(s).

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