Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 9d7f18d6c65bd17e…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:41:08 Authoring application: Microsoft Excel First seen: 2021-09-17
MD5: 4c433657ceb6eea7b5a02acb49a5e75a SHA-1: ba1bc257933e6f555bdd02639d4150153f0d63bc SHA-256: 9d7f18d6c65bd17ef348ee7ee84be68fcc27709b9acc67ea38127644f4972ffe
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 macros, indicated by the OLE_XLM_AUTOOPEN and OLE_XLM_DANGEROUS_FN heuristics. The presence of an 'Auto_Open' defined name suggests that the macro will execute automatically when the workbook is opened. The dangerous formula API usage (RUN=0) points towards the execution of arbitrary code, likely 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) 6760 bytes
SHA-256: 48ac1ce000575533681889599ee04501712fb9b61b3a78cc926a078bcf3f502d
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 -  CqKpGYz
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!E183 
' 0018     20 LABEL : Cell Value, String Constant - aYvme len=0 
' 0018     21 LABEL : Cell Value, String Constant - dGdSit len=0 
' 0018     20 LABEL : Cell Value, String Constant - DkEKr len=0 
' 0018     23 LABEL : Cell Value, String Constant - DXTAdzoF len=0 
' 0018     26 LABEL : Cell Value, String Constant - FLvqasdafJU len=0 
' 0018     23 LABEL : Cell Value, String Constant - fVZssiCi len=0 
' 0018     22 LABEL : Cell Value, String Constant - fzWunOd len=0 
' 0018     23 LABEL : Cell Value, String Constant - LODJhTyM len=0 
' 0018     25 LABEL : Cell Value, String Constant - LYPMuTzFMw len=0 
' 0018     20 LABEL : Cell Value, String Constant - qqdrS len=0 
' 0018     23 LABEL : Cell Value, String Constant - RFTjbcRq len=0 
' 0018     26 LABEL : Cell Value, String Constant - RNrXmMFNobF len=0 
' 0018     24 LABEL : Cell Value, String Constant - rybFCcDXD len=0 
' 0018     24 LABEL : Cell Value, String Constant - SKHcjBreO len=0 
' 0018     26 LABEL : Cell Value, String Constant - ugAUqhxaIux len=0 
' 0018     25 LABEL : Cell Value, String Constant - UVeDMzOXVs len=0 
' 0018     21 LABEL : Cell Value, String Constant - vnyfDK len=0 
' 0018     26 LABEL : Cell Value, String Constant - WUpwiNXWMwX len=0 
' 0018     22 LABEL : Cell Value, String Constant - ykWIZPo len=0 
' 0018     22 LABEL : Cell Value, String Constant - yPrfNsO 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 LAB
... (truncated)