Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 a008b2053d50a698…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:39:43 Authoring application: Microsoft Excel First seen: 2021-07-10
MD5: 5f92d9e3776eb8be9836d5cf05da1ef0 SHA-1: 8a2f76101fd2c449da42200b8031c89c4a27eb64 SHA-256: a008b2053d50a698c378e10bebe524177aa7204abf007584600df799830ccfba
140 Risk Score

Malware Insights

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

Static analysis revealed the presence of Excel 4.0 macros, specifically an Auto_Open function, which is a known technique for executing malicious code. The critical heuristic firings indicate the use of dangerous formula APIs within the macro, suggesting it's designed to run commands. The macro sheet itself contains a large amount of obfuscated data, likely containing the payload or instructions for further 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) 6552 bytes
SHA-256: ee61a00a919902f1ff9134333f56ee4e46ebacdac46749dc2ada617d3a861e5b
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 -  DNpvNDq
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!H139 
' 0018     23 LABEL : Cell Value, String Constant - aYAniGAY len=0 
' 0018     23 LABEL : Cell Value, String Constant - bCXByzbk len=0 
' 0018     23 LABEL : Cell Value, String Constant - bOXkorlR len=0 
' 0018     20 LABEL : Cell Value, String Constant - bxEWw len=0 
' 0018     23 LABEL : Cell Value, String Constant - DkRwzWuE len=0 
' 0018     22 LABEL : Cell Value, String Constant - dUkICIF len=0 
' 0018     27 LABEL : Cell Value, String Constant - dZUnlhwiNYFB len=0 
' 0018     22 LABEL : Cell Value, String Constant - EorXZYh len=0 
' 0018     22 LABEL : Cell Value, String Constant - hoUXrqM len=0 
' 0018     27 LABEL : Cell Value, String Constant - iTLNhIKojxJp len=0 
' 0018     27 LABEL : Cell Value, String Constant - jcpTrjRApmTB len=0 
' 0018     27 LABEL : Cell Value, String Constant - jvFlQsctqrNn len=0 
' 0018     22 LABEL : Cell Value, String Constant - KsZTDGE len=0 
' 0018     21 LABEL : Cell Value, String Constant - mDtXup len=0 
' 0018     21 LABEL : Cell Value, String Constant - mlyocG len=0 
' 0018     23 LABEL : Cell Value, String Constant - ogRjPoJT len=0 
' 0018     23 LABEL : Cell Value, String Constant - QexqEghg len=0 
' 0018     22 LABEL : Cell Value, String Constant - SPSQSvp len=0 
' 0018     20 LABEL : Cell Value, String Constant - uZiXS len=0 
' 0018     27 LABEL : Cell Value, String Constant - YIgiBbBqcUnc 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 
... (truncated)

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