Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 78cd9dc1f02906da…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:34:58 Authoring application: Microsoft Excel First seen: 2021-10-23
MD5: 0956c6a71617067b994cf77f463cd3f5 SHA-1: bf18e728b30c8ff0004e905ab0d36032e9bf7086 SHA-256: 78cd9dc1f02906da03890eda4cb164b0f348f24ad9b44963f097ac325346801b
140 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro-enabled workbook containing an Auto_Open defined name, which is a critical indicator of malicious intent. This technique allows for the automatic execution of code upon opening the workbook, likely to download and execute a secondary payload. The presence of dangerous formula APIs further supports this assessment.

Heuristics 3

  • 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.
  • XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6405 bytes
SHA-256: 647f9c3addf2944468ab0bb6fc31c15aed1fee3b2174cee2838a19a9ae5aaa1e
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     13 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  Cmcf
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!H129 
' 0018     26 LABEL : Cell Value, String Constant - CjQVMivONrL len=0 
' 0018     23 LABEL : Cell Value, String Constant - cTVkMPsQ len=0 
' 0018     27 LABEL : Cell Value, String Constant - dqCfdSllsTgk len=0 
' 0018     26 LABEL : Cell Value, String Constant - EpBlUHwvWJq len=0 
' 0018     23 LABEL : Cell Value, String Constant - FbGbRYoo len=0 
' 0018     22 LABEL : Cell Value, String Constant - hPUHFKF len=0 
' 0018     21 LABEL : Cell Value, String Constant - IriNvU len=0 
' 0018     24 LABEL : Cell Value, String Constant - JburwAzyz len=0 
' 0018     21 LABEL : Cell Value, String Constant - lnYCyn len=0 
' 0018     20 LABEL : Cell Value, String Constant - MYHgK len=0 
' 0018     26 LABEL : Cell Value, String Constant - nObDaApCHQq len=0 
' 0018     26 LABEL : Cell Value, String Constant - nPcKEAoBJIm len=0 
' 0018     25 LABEL : Cell Value, String Constant - NteXtSoRyg len=0 
' 0018     23 LABEL : Cell Value, String Constant - SHHpIZaN len=0 
' 0018     23 LABEL : Cell Value, String Constant - tBtLIKPx len=0 
' 0018     25 LABEL : Cell Value, String Constant - tpprJPuIjN len=0 
' 0018     22 LABEL : Cell Value, String Constant - TUXoIXy len=0 
' 0018     22 LABEL : Cell Value, String Constant - WtAsEeK len=0 
' 0018     26 LABEL : Cell Value, String Constant - WzAAxIEDiiF len=0 
' 0018     22 LABEL : Cell Value, String Constant - xVaLLYq len=0 
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd   
... (truncated)

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