Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 f796089c9b1075e8…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:42:42 Authoring application: Microsoft Excel First seen: 2021-10-04
MD5: 72ffc41cd64edd09677d94243d29a2d7 SHA-1: e0f3b8840bd16901ffed4c1ddd61121d2c1eec85 SHA-256: f796089c9b1075e8145fa72f48803348084c594d2bb085ff14b2ecea954500d4
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, specifically an Auto_Open macro. This macro is designed to execute arbitrary commands, as indicated by the 'RUN=0' and 'risky-formula=2' heuristic firings. The macro sheet itself contains a large amount of obfuscated data, suggesting it is intended to download and execute a secondary 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) 6608 bytes
SHA-256: 3227a65515462f6804b008de3b0b7af5f25da19931d30c21597d0b271a8b6d5a
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     15 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  pVIJyD
' 0018     20 LABEL : Cell Value, String Constant - ADMGD len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!H188 
' 0018     27 LABEL : Cell Value, String Constant - BqfgjvzOZxiK len=0 
' 0018     23 LABEL : Cell Value, String Constant - BvBWacmm len=0 
' 0018     23 LABEL : Cell Value, String Constant - byvFaqtc len=0 
' 0018     21 LABEL : Cell Value, String Constant - CTtvDd len=0 
' 0018     26 LABEL : Cell Value, String Constant - dTXBvNbIvcD len=0 
' 0018     20 LABEL : Cell Value, String Constant - eMJyo len=0 
' 0018     26 LABEL : Cell Value, String Constant - ffcPXHYAJUh len=0 
' 0018     20 LABEL : Cell Value, String Constant - jAePf len=0 
' 0018     27 LABEL : Cell Value, String Constant - jhhjHGZuyRQn len=0 
' 0018     23 LABEL : Cell Value, String Constant - jshfeEGQ len=0 
' 0018     20 LABEL : Cell Value, String Constant - NlHlm len=0 
' 0018     20 LABEL : Cell Value, String Constant - oeQRQ len=0 
' 0018     22 LABEL : Cell Value, String Constant - PtIraCw len=0 
' 0018     21 LABEL : Cell Value, String Constant - RQPjEk len=0 
' 0018     25 LABEL : Cell Value, String Constant - shbMoNQkoX len=0 
' 0018     22 LABEL : Cell Value, String Constant - tDMDXFY len=0 
' 0018     20 LABEL : Cell Value, String Constant - tPCxm len=0 
' 0018     20 LABEL : Cell Value, String Constant - wUUkH len=0 
' 0018     21 LABEL : Cell Value, String Constant - xwUJxM 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 LABELSST : Cell Val
... (truncated)

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