Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 ca43051a15b2c90a…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:45:18 Authoring application: Microsoft Excel First seen: 2021-10-23
MD5: 7084f767b00212d57626aa3653f384ca SHA-1: a91df39c801b4f3795d803ac676bbb0308f850ae SHA-256: ca43051a15b2c90ae35d1942ab70bec2db9bf25c35af6a24c1ee56db55469b18
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 detected with critical heuristics for Auto_Open execution and dangerous formula APIs. The presence of an Auto_Open entry indicates that the macro will execute automatically upon opening the workbook, which is a common technique for initial execution of malicious payloads. The specific dangerous function identified is RUN, suggesting the macro is intended to launch an external process.

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) 6550 bytes
SHA-256: 1abd9b2f46d8899d44da80e68692d656460b97966a113799a4657e8f53ec6f15
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     16 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  vklPPyl
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!I164 
' 0018     25 LABEL : Cell Value, String Constant - bTIYLAdooS len=0 
' 0018     23 LABEL : Cell Value, String Constant - CmHjCfON len=0 
' 0018     26 LABEL : Cell Value, String Constant - dxMdeYlNWCf len=0 
' 0018     20 LABEL : Cell Value, String Constant - JIMKD len=0 
' 0018     27 LABEL : Cell Value, String Constant - kfMPTOjqjbck len=0 
' 0018     23 LABEL : Cell Value, String Constant - kjglrstp len=0 
' 0018     20 LABEL : Cell Value, String Constant - krbyC len=0 
' 0018     21 LABEL : Cell Value, String Constant - ldOExc len=0 
' 0018     27 LABEL : Cell Value, String Constant - MoNDtduDPFYd len=0 
' 0018     23 LABEL : Cell Value, String Constant - mvRzdxvs len=0 
' 0018     24 LABEL : Cell Value, String Constant - nqjkOLRel len=0 
' 0018     25 LABEL : Cell Value, String Constant - ovSylwAArO len=0 
' 0018     25 LABEL : Cell Value, String Constant - puXQjCjAMY len=0 
' 0018     23 LABEL : Cell Value, String Constant - QtHWeTPi len=0 
' 0018     20 LABEL : Cell Value, String Constant - qvNVs len=0 
' 0018     26 LABEL : Cell Value, String Constant - RPsUSDiWnfC len=0 
' 0018     21 LABEL : Cell Value, String Constant - RyqQwU len=0 
' 0018     20 LABEL : Cell Value, String Constant - wBKvG len=0 
' 0018     20 LABEL : Cell Value, String Constant - YXvhT len=0 
' 0018     26 LABEL : Cell Value, String Constant - ZSrbeqRGvHI 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     10 
... (truncated)

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