Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 e5f28565c7e0dd68…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:42:30 Authoring application: Microsoft Excel First seen: 2021-07-10
MD5: 7afdbe0e87f9270c95be6dbe37be195b SHA-1: 8fa465dd2d6e6acad19e979b7c43d61b9678c3e0 SHA-256: e5f28565c7e0dd680d32f300a937c52e1fef71442770e21178a1ddd6af17d10c
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The sample is an Excel file containing Excel 4.0 (XLM) macros. The critical heuristic firings indicate the presence of an Auto_Open defined name, which is a common method for automatically executing malicious code when the workbook is opened. This suggests the file is intended to act as a downloader for a secondary stage payload.

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) 6855 bytes
SHA-256: 4c41972b4a455cb55a3ba08a628d6dcfdd3ede6cd511fae4e1bcb25b7429ea99
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     20 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  aimXqSaiXZl
' 0018     26 LABEL : Cell Value, String Constant - afVZNLbilZn len=0 
' 0018     27 LABEL : Cell Value, String Constant - aLNnArjBgDPB len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!D182 
' 0018     20 LABEL : Cell Value, String Constant - CgiqU len=0 
' 0018     26 LABEL : Cell Value, String Constant - dNxAKJnGFod len=0 
' 0018     25 LABEL : Cell Value, String Constant - egbJpORvkG len=0 
' 0018     26 LABEL : Cell Value, String Constant - hSpeZQSBaic len=0 
' 0018     24 LABEL : Cell Value, String Constant - iAdGzdBBo len=0 
' 0018     20 LABEL : Cell Value, String Constant - IVWow len=0 
' 0018     21 LABEL : Cell Value, String Constant - NREgHq len=0 
' 0018     21 LABEL : Cell Value, String Constant - qGwoQB len=0 
' 0018     26 LABEL : Cell Value, String Constant - qJQIXsEVECE len=0 
' 0018     22 LABEL : Cell Value, String Constant - shvQwQQ len=0 
' 0018     25 LABEL : Cell Value, String Constant - TrxXdrzclb len=0 
' 0018     22 LABEL : Cell Value, String Constant - tWBWDPY len=0 
' 0018     22 LABEL : Cell Value, String Constant - tXMYbdZ len=0 
' 0018     23 LABEL : Cell Value, String Constant - vJuPmVSV len=0 
' 0018     27 LABEL : Cell Value, String Constant - vkrrkUKRcKUN len=0 
' 0018     21 LABEL : Cell Value, String Constant - XLXxox len=0 
' 0018     24 LABEL : Cell Value, String Constant - YKLWRhwao len=0 
' 0018     20 LABEL : Cell Value, String Constant - ZIvsB 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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