Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 5be5612388be5e1f…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:46:01 Authoring application: Microsoft Excel First seen: 2021-09-27
MD5: 05c9be62ef083304c32dc0f110bb71ec SHA-1: 4b946fbd9902ec2e0c527c36916bb3dec8baad54 SHA-256: 5be5612388be5e1f1174ef72298ecaa412387d6a39db8d4f3dd8c3a454ac1f32
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open function, which is a known method for executing malicious code within older Excel versions. The critical heuristics indicate the presence of dangerous formula APIs within the Auto_Open macro, suggesting an intent to run arbitrary commands. No specific URLs or further payloads were extracted, but the mechanism itself is highly suspicious.

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) 6726 bytes
SHA-256: 208f85dc7214c969ba60c69aa32e2ff0762ed877e68de7ce19385f6fc7ac8117
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     17 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  KIJBYnjz
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!I136 
' 0018     20 LABEL : Cell Value, String Constant - byMUE len=0 
' 0018     27 LABEL : Cell Value, String Constant - CzCutSdZuOkZ len=0 
' 0018     24 LABEL : Cell Value, String Constant - dsCbSzHru len=0 
' 0018     25 LABEL : Cell Value, String Constant - fRXparHllk len=0 
' 0018     25 LABEL : Cell Value, String Constant - ijEqtdXger len=0 
' 0018     20 LABEL : Cell Value, String Constant - ioXOp len=0 
' 0018     21 LABEL : Cell Value, String Constant - IsGCLg len=0 
' 0018     23 LABEL : Cell Value, String Constant - JFjVRoYS len=0 
' 0018     24 LABEL : Cell Value, String Constant - Leaqygpon len=0 
' 0018     20 LABEL : Cell Value, String Constant - mTECf len=0 
' 0018     23 LABEL : Cell Value, String Constant - nWhvlnqS len=0 
' 0018     21 LABEL : Cell Value, String Constant - oFluFg len=0 
' 0018     26 LABEL : Cell Value, String Constant - OoIXYstZtEE len=0 
' 0018     20 LABEL : Cell Value, String Constant - orVcj len=0 
' 0018     27 LABEL : Cell Value, String Constant - pXuaqGBZAKDM len=0 
' 0018     25 LABEL : Cell Value, String Constant - qvFFoTTfSQ len=0 
' 0018     25 LABEL : Cell Value, String Constant - SdmYUNTLFR len=0 
' 0018     26 LABEL : Cell Value, String Constant - vcuEubpscFP len=0 
' 0018     25 LABEL : Cell Value, String Constant - vvVtfdUxSk len=0 
' 0018     22 LABEL : Cell Value, String Constant - YzrayUx 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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