Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b1dbf09e5ddacffd…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:41:48 Authoring application: Microsoft Excel First seen: 2021-10-23
MD5: 4542dd516b206136a47ca7c6792dbfc1 SHA-1: 374db8101194c493d609d9822b9eb3fe36bcf591 SHA-256: b1dbf09e5ddacffd917c577fc4570d75212543f08712fb3cafd02da0d2a2f445
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 suggests the macro is designed to execute arbitrary commands. This is a common technique for downloading and executing further malicious content.

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) 6640 bytes
SHA-256: 751f39caff17fe7cede087a0fdc70a9e14dab8ffc5aba8c4a19a754d33f3271c
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     19 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  dJTFYZyPtM
' 0018     25 LABEL : Cell Value, String Constant - aKeiUMzaCK len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!D150 
' 0018     26 LABEL : Cell Value, String Constant - bJUUpveQoJg len=0 
' 0018     25 LABEL : Cell Value, String Constant - bwHUkaCKbp len=0 
' 0018     21 LABEL : Cell Value, String Constant - CYqRtM len=0 
' 0018     26 LABEL : Cell Value, String Constant - eFWbiPFRsks len=0 
' 0018     26 LABEL : Cell Value, String Constant - EfxkHiuzRBt len=0 
' 0018     25 LABEL : Cell Value, String Constant - etQNTaTobh len=0 
' 0018     20 LABEL : Cell Value, String Constant - EXTjf len=0 
' 0018     21 LABEL : Cell Value, String Constant - EzjObU len=0 
' 0018     20 LABEL : Cell Value, String Constant - FBjtj len=0 
' 0018     24 LABEL : Cell Value, String Constant - JYaRoJffu len=0 
' 0018     26 LABEL : Cell Value, String Constant - KVJbqLLmeGB len=0 
' 0018     24 LABEL : Cell Value, String Constant - KyZkpecaa len=0 
' 0018     23 LABEL : Cell Value, String Constant - MfbiRKOJ len=0 
' 0018     24 LABEL : Cell Value, String Constant - mKwudtOXP len=0 
' 0018     26 LABEL : Cell Value, String Constant - pgJlfKjLHII len=0 
' 0018     23 LABEL : Cell Value, String Constant - UtgmsgjF len=0 
' 0018     23 LABEL : Cell Value, String Constant - XLPKJVFQ len=0 
' 0018     24 LABEL : Cell Value, String Constant - YmnQbzRzG len=0 
' 0018     27 LABEL : Cell Value, String Constant - ysrOMHUplyHh 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/ S
... (truncated)

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