Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 376d6e1e3a7b6515…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:44:26 Authoring application: Microsoft Excel First seen: 2021-10-11
MD5: 362fdde60f975c88f10c6f1070641889 SHA-1: 6ef98b53d74e73271f787d8496a5e0c3f2b83cfd SHA-256: 376d6e1e3a7b65152a0e412fa78b1e06c61d052e20a630c418c40005d824c74f
140 Risk Score

Malware Insights

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

The file is an Excel document containing Excel 4.0 macros, specifically an Auto_Open function. This function is designed to execute automatically when the workbook is opened. The presence of dangerous formula APIs like RUN indicates that the macro is intended to execute arbitrary code, likely downloading and running a second-stage payload. No specific family could be identified.

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) 6627 bytes
SHA-256: 5a1322f6bbf046b8c73ea033288acef73e1de8122a55e80d3dfc46b03667729a
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 -  rNUkSrSF
' 0018     24 LABEL : Cell Value, String Constant - agUhXvpqy len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!A176 
' 0018     22 LABEL : Cell Value, String Constant - avtUKAZ len=0 
' 0018     22 LABEL : Cell Value, String Constant - BkJMvfJ len=0 
' 0018     26 LABEL : Cell Value, String Constant - BlJKVRfuqbi len=0 
' 0018     20 LABEL : Cell Value, String Constant - bsxan len=0 
' 0018     25 LABEL : Cell Value, String Constant - cZtvYmATmp len=0 
' 0018     25 LABEL : Cell Value, String Constant - dKSYUQIEkT len=0 
' 0018     24 LABEL : Cell Value, String Constant - ECleqruAe len=0 
' 0018     23 LABEL : Cell Value, String Constant - FLmveMtX len=0 
' 0018     27 LABEL : Cell Value, String Constant - HyZzhSVXkJyx len=0 
' 0018     27 LABEL : Cell Value, String Constant - iSqKKyQeLPvU len=0 
' 0018     26 LABEL : Cell Value, String Constant - jtDELTHyakO len=0 
' 0018     21 LABEL : Cell Value, String Constant - PaZKkK len=0 
' 0018     21 LABEL : Cell Value, String Constant - qhCVxf len=0 
' 0018     21 LABEL : Cell Value, String Constant - SGUbHe len=0 
' 0018     21 LABEL : Cell Value, String Constant - SIKKtP len=0 
' 0018     27 LABEL : Cell Value, String Constant - SMkycvSAhtyT len=0 
' 0018     27 LABEL : Cell Value, String Constant - umBKZThoPPVu len=0 
' 0018     25 LABEL : Cell Value, String Constant - UtoIXyJrMX len=0 
' 0018     24 LABEL : Cell Value, String Constant - WjPHGivCs 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

... (truncated)

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