Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 316ad1e603db158d…

MALICIOUS

Office (OOXML)

746.5 KB Created: 2020-05-11 14:19:29 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2020-12-25
MD5: ac420726ba595ef0efcc3a5624a661d1 SHA-1: af6c008f5d8fdcde23153d80859c7b3d8db35edd SHA-256: 316ad1e603db158d05da361375b4c31a87492b3f52068bb4051082ad504b4087
182 Risk Score

Malware Insights

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

The file contains critical heuristic firings indicating the presence of Excel 4.0 macros, including WinAPI and download strings. The macros reconstruct the URL 'http://tai.ie/21.gif' and likely use WinAPI functions such as URLDownloadToFileA to download and execute a second-stage payload, which is a common technique for malware distribution.

Heuristics 4

  • Excel 4.0 macro sheet (1 sheet(s)) critical 2 related findings 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. The macro sheet is stored as XLSB/BIFF12 binary content, which many XML-only OOXML scanners miss.
  • Binary XLM macro sheet with WinAPI/download strings critical OOXML_XLM_BINARY_WINAPI_STRINGS
    Excel 4.0 macro sheet is stored as BIFF12/XLSB binary data and contains Win32 download or process-execution API strings such as URLDownloadToFileA, ShellExecuteA, or CreateDirectoryA. These strings are high-signal in XLM macro sheets and catch payload-download macros that XML-formula scanners cannot parse.
  • URL reconstructed from XLM cell array (1 URL) critical OOXML_XLM_CELL_ARRAY_URL
    Excel 4.0 macro sheet stages its payload URL across individual numeric cells (one ASCII charcode per cell), inside an embedded HTA that uses VBScript Chr()/&-concat obfuscation, or split across multi-char fragment cells a download formula concatenates by reference (=A1&A2&… / CONCATENATE(...)). The reconstructed URL is invisible to literal-bytes URL extraction because it is never contiguous in the workbook stream. URLs were recovered by walking the BIFF12 record stream of every worksheet and macrosheet part and decoding RK/inline-string/shared-string cells in row-major and column-major order plus FORMULA cell-reference concatenation in token order.
  • 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://tai.ie/21.gif Referenced by macro

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.bin xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.bin 53822 bytes
SHA-256: 2476e5bf99fc71b06618a9179d36f2fbdd2ecf91537129b33c40f53b1029d304
Preview script
First 1,000 lines of the extracted script
�  �  �   @      ��������    �      �       �   �  �  �     D   �   @   d           � $    ^   �           ^   ^   �   �   �  �  %      ��    & �  ����        �  <         �         <         �         <         8,        <                   < �   �   q         �  �  %      ��    &                        �    &�           E       DG      �  Ao     %      ��    &                        �   	!                      D     �     �         �   F E R T R J H T R J H T G R H J Y T Y T Y T T G R H J G T R H T R G H H T H J T J H G T R J H T R H J T G R H J T R H J T R G H J T G R H J T G R H J G T R H T R T H J H J T R T R H T R J T R G H J G T R H J G T R H J G T R J H T G R H J G T R J H G T R H J R T G H J G T R H G T R H T G R H T G R H T R T G T G R T R H J T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T H T G H H G T J G T J G T R H J T G R H J R T G H J R T G H J   �    � F E R T R J H T R J H T G R H J Y T Y T Y T T G R H J G T R H T R G H H T H J T J H G T R J H T R H J T G R H J T R H J T R G H J T G R H J T G R H J G T R H T R T H J H J T R T R H T R J T R G H J G T R H J G T R H J G T R J H T G R H J G T R J H G T R H J R T G H J G T R H G T R H T G R H T G R H T R T G T G R T R H J T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T H T G H H G T J G T J G T R H J T G R H J R T G H J R T G H J    R T A0     %      ��    &                        �    �         �   F E R Y T T Y T Y T R J H T R J H T G R H J T G R H J G T R H T R G H H T H J T J H G T R J H T R H J T G R H J T R H J T R G H J T G R H J T G R H J G T R H T R T H J H J T R T R H T R J T R G H J G T R H J G T R H J G T R J H T G R H J G T R J H G T R H J R T G H J G T R H G T R H T G R H T G R H T R T G T G R T R H J T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T H T G H H G T J G T J G T R H J T G R H J R T G H J R T Y T Y T Y T Y T T Y G H J   �    � F E R Y T T Y T Y T R J H T R J H T G R H J T G R H J G T R H T R G H H T H J T J H G T R J H T R H J T G R H J T R H J T R G H J T G R H J T G R H J G T R H T R T H J H J T R T R H T R J T R G H J G T R H J G T R H J G T R J H T G R H J G T R J H G T R H J R T G H J G T R H G T R H T G R H T G R H T R T G T G R T R H J T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T H T G H H G T J G T J G T R H J T G R H J R T G H J R T Y T Y T Y T Y T T Y G H J    R T A0      �         �   F E R T R J H T R J H T G R H J T G R H J G T R H T R G H H T H J T J H G T R J H T R H J T G R H J T R H J T R G H J T G R H J T G R H J G T R H T R T H J H J T R T R H T R J T R G H J G T R H J G T R H J G T R J H T G R H J G T R J H G T G F G R H J R T G H J G T R H G T R H T G R H T G R H T R T G T G R T R H J T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T H T G H H G T F G T X G T R H J T G R H J R T G H J R T G H J   �    � F E R T R J H T R J H T G R H J T G R H J G T R H T R G H H T H J T J H G T R J H T R H J T G R H J T R H J T R G H J T G R H J T G R H J G T R H T R T H J H J T R T R H T R J T R G H J G T R H J G T R H J G T R J H T G R H J G T R J H G T G F G R H J R T G H J G T R H G T R H T G R H T G R H T R T G T G R T R H J T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T T H T G H H G T F G T X G T R H J T G R H J R T G H J R T G H J    R T A0     %      ��    &                        �   
 �              $�   5 B  �      �              C        %      ��    &                        �   	!                      D     �    %      ��    &                        �   
 q              $�   � B  �      �        �V@%      ��    &                        �   	!                      D     �    	!�                     D    ��    %      ��    &                        �    �         �   F E R T R J H T R J H T G R H J T G R H J G T R H T R G H H T H J T J H G T R J H T R H J T G R H J T R H J T R G H J T G R H J T G R H J G T R H T R T H J H J T R T R H T R J T R G H J G T R H J G T R H J G T R J H T G R H J G T R J H G T R H J R T G H J G T R H G T R H T G R H T G R H T R
... (truncated)

Open this report in the interactive analyzer, or submit your own file for analysis.