Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 9c9eaaf60c6a9219…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-25 10:39:08 Authoring application: Microsoft Excel First seen: 2021-06-28
MD5: 4bb25e634462a0ca8dce7b6512950e9d SHA-1: 5ea31a269e8f7dc5fbc0400567301e93cada953e SHA-256: 9c9eaaf60c6a9219a00f09de54b50cd581590fc42be3e9c0027edd63f0820a3b
140 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro sheet that contains an Auto_Open defined name, indicating it will execute automatically when opened. Heuristics indicate the use of dangerous formula APIs, specifically RUN=0, which is commonly used to execute arbitrary code. This suggests the macro is designed 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) 6420 bytes
SHA-256: 271a3b1595b4ed14916f6ae8a1da2b44d588096aef54f5bdfd30c80b189fe975
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     14 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  KZwjv
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!H183 
' 0018     24 LABEL : Cell Value, String Constant - buvbCSgYb len=0 
' 0018     20 LABEL : Cell Value, String Constant - bxOXr len=0 
' 0018     26 LABEL : Cell Value, String Constant - FbiFveojccM len=0 
' 0018     21 LABEL : Cell Value, String Constant - fYmhMb len=0 
' 0018     25 LABEL : Cell Value, String Constant - jCrQCYJSSQ len=0 
' 0018     23 LABEL : Cell Value, String Constant - JMHYhRoz len=0 
' 0018     21 LABEL : Cell Value, String Constant - NdlXIA len=0 
' 0018     20 LABEL : Cell Value, String Constant - ngfQy len=0 
' 0018     24 LABEL : Cell Value, String Constant - NZIgXeBMO len=0 
' 0018     26 LABEL : Cell Value, String Constant - oAxNjEvOAYt len=0 
' 0018     21 LABEL : Cell Value, String Constant - pZTtgk len=0 
' 0018     23 LABEL : Cell Value, String Constant - QbnnGFxG len=0 
' 0018     22 LABEL : Cell Value, String Constant - rJArXKc len=0 
' 0018     20 LABEL : Cell Value, String Constant - SCfVo len=0 
' 0018     27 LABEL : Cell Value, String Constant - SpYrcQPjjZFF len=0 
' 0018     25 LABEL : Cell Value, String Constant - TCyElpxzOJ len=0 
' 0018     23 LABEL : Cell Value, String Constant - VHbCUKBP len=0 
' 0018     21 LABEL : Cell Value, String Constant - WWIFBe len=0 
' 0018     23 LABEL : Cell Value, String Constant - xOFsHCci len=0 
' 0018     27 LABEL : Cell Value, String Constant - zFEEGTAwWLYW 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 LABEL
... (truncated)

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