Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b4c18984221a09b8…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-27 11:46:44 Authoring application: Microsoft Excel First seen: 2021-09-27
MD5: 78ddc17197e2f75342acd57e362b8041 SHA-1: 8d8c9a4159e24cc89ec8125b6649f06f91c317ae SHA-256: b4c18984221a09b830d9bd9e7c9c0742ab5cc8aef7086fcd1135d0e385c791ca
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. The presence of dangerous formula APIs like RUN indicates an intent to execute arbitrary commands. While the specific payload is not directly visible, the macro's structure suggests it's designed to download and execute a second-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) 6637 bytes
SHA-256: 7e98116cb43794b148699821512588bb1cc0f56b2803142666b4b68210364bcc
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     15 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  peYaJR
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!H171 
' 0018     24 LABEL : Cell Value, String Constant - aVbvkbtwq len=0 
' 0018     26 LABEL : Cell Value, String Constant - azTGdyjblPi len=0 
' 0018     22 LABEL : Cell Value, String Constant - dPaGIFF len=0 
' 0018     20 LABEL : Cell Value, String Constant - ejtKb len=0 
' 0018     24 LABEL : Cell Value, String Constant - FtCtaEZnE len=0 
' 0018     22 LABEL : Cell Value, String Constant - hSeUxuI len=0 
' 0018     25 LABEL : Cell Value, String Constant - ifgRBybpcL len=0 
' 0018     20 LABEL : Cell Value, String Constant - IGUNV len=0 
' 0018     21 LABEL : Cell Value, String Constant - IStcMF len=0 
' 0018     25 LABEL : Cell Value, String Constant - ITnguDYfjx len=0 
' 0018     25 LABEL : Cell Value, String Constant - ketbrSPcZR len=0 
' 0018     22 LABEL : Cell Value, String Constant - kHlzrkS len=0 
' 0018     23 LABEL : Cell Value, String Constant - oGcwTxnB len=0 
' 0018     23 LABEL : Cell Value, String Constant - PLLcqtFF len=0 
' 0018     25 LABEL : Cell Value, String Constant - qJWXZiSGmY len=0 
' 0018     21 LABEL : Cell Value, String Constant - raDCsT len=0 
' 0018     23 LABEL : Cell Value, String Constant - SDTNcCuM len=0 
' 0018     20 LABEL : Cell Value, String Constant - TbGZW len=0 
' 0018     21 LABEL : Cell Value, String Constant - uQlWuT len=0 
' 0018     26 LABEL : Cell Value, String Constant - vxYMAuHAPQR 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 LABELSST
... (truncated)

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