Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 9cbab71e6235495d…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-25 10:35:48 Authoring application: Microsoft Excel First seen: 2021-11-02
MD5: f4fae33a4a6cae010afc4b8d9ad98b9c SHA-1: 58d9d7ff0f2f480575671746469f05ff9d40e046 SHA-256: 9cbab71e6235495d6482ce64792e01da2e6de95677a9fb1d3d724395b38dfc45
140 Risk Score

Malware Insights

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

The sample is an Excel file containing Excel 4.0 (XLM) macros, specifically triggering an Auto_Open function. This indicates an attempt to automatically execute malicious code when the workbook is opened. The presence of dangerous formula APIs like RUN suggests the macro is intended to download and execute a second-stage payload, a common technique for initial execution.

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) 6636 bytes
SHA-256: eddeefc4dae1b74eb41bd622fdaaf909ad6ce3b2a0529d0bd24dfa4ce7a9a2c4
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     18 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  xeciNDmpQ
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!E151 
' 0018     25 LABEL : Cell Value, String Constant - AxDlWDleNY len=0 
' 0018     23 LABEL : Cell Value, String Constant - CydHieNb len=0 
' 0018     25 LABEL : Cell Value, String Constant - CZCxCcHyAZ len=0 
' 0018     27 LABEL : Cell Value, String Constant - dZndhRaXpfKo len=0 
' 0018     26 LABEL : Cell Value, String Constant - ELBnpMMCFfh len=0 
' 0018     21 LABEL : Cell Value, String Constant - fmWYWt len=0 
' 0018     25 LABEL : Cell Value, String Constant - fZHNoMAGpi len=0 
' 0018     23 LABEL : Cell Value, String Constant - jMBHjQah len=0 
' 0018     20 LABEL : Cell Value, String Constant - kMiYB len=0 
' 0018     22 LABEL : Cell Value, String Constant - lbXTtIX len=0 
' 0018     23 LABEL : Cell Value, String Constant - MADAiYhh len=0 
' 0018     22 LABEL : Cell Value, String Constant - MTBbgae len=0 
' 0018     26 LABEL : Cell Value, String Constant - OejSLGYnGIA len=0 
' 0018     24 LABEL : Cell Value, String Constant - olDPZqhTA len=0 
' 0018     20 LABEL : Cell Value, String Constant - reGaR len=0 
' 0018     24 LABEL : Cell Value, String Constant - rppEyxYOY len=0 
' 0018     27 LABEL : Cell Value, String Constant - SMUyVvQLRsSt len=0 
' 0018     25 LABEL : Cell Value, String Constant - tTNMBrMtrN len=0 
' 0018     22 LABEL : Cell Value, String Constant - XPGbqBb len=0 
' 0018     20 LABEL : Cell Value, String Constant - ylMIG 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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