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

Static analysis result for SHA-256 63aaa264c243b2de…

MALICIOUS

Office (OOXML) / .XLSX

216.1 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300
MD5: dc6a91012a2bd781b0e1054b0e903c1a SHA-1: 8f342270193c26849ddd5b126043a89473102312 SHA-256: 63aaa264c243b2dea7e063adc393276a84aa7a8bbc2c204b14538b97d26523a9
210 Risk Score

Malware Insights

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

The sample contains Excel 4.0 macros (XLM) which are known to be used for malicious purposes. These macros utilize dangerous functions like FORMULA and EXEC to download and execute payloads from the provided URLs. The Auto_Open macro is present, indicating an attempt to automatically run the malicious code upon opening the document. The presence of multiple suspicious URLs suggests a downloader functionality.

Heuristics 7

  • Excel 4.0 macro sheet (3 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.
  • Dangerous XLM formula APIs: FORMULA, GOTO, HALT, REGISTER, EXEC 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.
  • Auto_Open macro high OLE_VBA_AUTO
    Auto_Open macro
  • VBA project inside OOXML medium OOXML_VBA
    Document contains a VBA project — VBA macros present
  • 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 3 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 http://5.34.180.57/
    • http://45.138.157.216/
    • http://45.12.32.131/
    • http://5.34.180.57/44313,6048108796.dat
    • http://45.138.157.216/44313,6048108796.dat
    • http://45.12.32.131/44313,6048108796.dat
    • 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
    • http://schemas.microsoft.com/office/spreadsheetml/2014/revision
    • http://schemas.microsoft.com/office/spreadsheetml/2015/revision2
    • http://schemas.microsoft.com/office/spreadsheetml/2016/revision3
    • http://schemas.microsoft.com/office/spreadsheetml/2016/revision6

Extracted artifacts 5

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
5b8703c963ccff58b2fe5575bbc6e69f0df0597a77d0f2f9ac7619e250577a21
vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 2651 bytes
vbaProject_00.bin
4af5a69b72686ae2f95f829c98e98f406dae10333748edcada85b24b68aeebef
vba-project OOXML VBA project: xl/vbaProject.bin 12288 bytes
xlm_sheet_00.xml
f90092cc573c0044407cb440d829560b618b9bf3234fc08e39504c578c519997
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 4198 bytes
xlm_sheet_01.xml
0a66b50328ea57abfd0fba95f93001e89e484283026f92736f861e28fb7eaa14
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 2097 bytes
xlm_sheet_02.xml
5e80fd069ac35c5e39918d8dfaaf0ba77875f57b487bcfcc5d8bc7d346806551
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet3.xml 1832 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 shell/COM execution token(s).