Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 84bfcd358ce27941…

MALICIOUS

Office (OLE)

37.0 KB Created: 2020-11-25 10:42:05 Authoring application: Microsoft Excel First seen: 2021-10-02
MD5: 4e57f4116317e74171c6ffc0dd81e995 SHA-1: 1608f51a34fd5c40cf5d676f28ce5273a9e2e697 SHA-256: 84bfcd358ce2794162755a5c1be19cd03ce3ba979de27bf8cd00a48d0fdbe3b9
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 defined name, which is a critical finding indicating automatic execution upon opening. The presence of dangerous formula APIs like RUN further suggests malicious intent. While the exact payload is not discernible from the provided macro code, the Auto_Open function is designed to execute arbitrary commands, likely leading to the download and execution of 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) 6623 bytes
SHA-256: 5855159825f8314acb6ad4b714a6da93449b643638ed701f46c1a317cd3bd871
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 -  UDByyeK
' 0018     24 LABEL : Cell Value, String Constant - AqtcLqkgy len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!A176 
' 0018     21 LABEL : Cell Value, String Constant - CSoHSc len=0 
' 0018     27 LABEL : Cell Value, String Constant - ExEsFVshBhgp len=0 
' 0018     21 LABEL : Cell Value, String Constant - jpqGjY len=0 
' 0018     24 LABEL : Cell Value, String Constant - JYLRpEakf len=0 
' 0018     26 LABEL : Cell Value, String Constant - KTmDOYtmUJj len=0 
' 0018     22 LABEL : Cell Value, String Constant - LnzQrYn len=0 
' 0018     20 LABEL : Cell Value, String Constant - mqNIb len=0 
' 0018     25 LABEL : Cell Value, String Constant - mTBppomhKB len=0 
' 0018     22 LABEL : Cell Value, String Constant - OYEtWVv len=0 
' 0018     27 LABEL : Cell Value, String Constant - tCloxdzcohOw len=0 
' 0018     23 LABEL : Cell Value, String Constant - udYEfBrZ len=0 
' 0018     24 LABEL : Cell Value, String Constant - UkTTPugYV len=0 
' 0018     24 LABEL : Cell Value, String Constant - vVFrbLUSS len=0 
' 0018     20 LABEL : Cell Value, String Constant - WDjuE len=0 
' 0018     22 LABEL : Cell Value, String Constant - WPCpVGR len=0 
' 0018     21 LABEL : Cell Value, String Constant - XAeQVh len=0 
' 0018     25 LABEL : Cell Value, String Constant - ZHFkveSUAt len=0 
' 0018     24 LABEL : Cell Value, String Constant - ZkTcZnLZS len=0 
' 0018     23 LABEL : Cell Value, String Constant - zpyvkRdO 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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