Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 510a01b496da87cb…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:47:46 Authoring application: Microsoft Excel First seen: 2021-10-12
MD5: f8766da108afe880ead3127f02f34983 SHA-1: c882003816f876fb8787eb282ef4f13d1174ef73 SHA-256: 510a01b496da87cb147794f3b92509421163376a9defb64743c1ce39dd5787cc
140 Risk Score

Malware Insights

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

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open entry, which is a common technique for executing malicious code. The macro sheet contains a reference to a dangerous formula API, suggesting it's designed to perform harmful actions. While the exact payload is not discernible from the truncated evidence, the Auto_Open function strongly implies an attempt to execute arbitrary code upon file opening.

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) 6784 bytes
SHA-256: e3585ae1ebe3bcff678ea3130fe815696ff4990b464dc7831916faf1730c6cb3
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     18 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  IxdRjHWjY
' 0018     21 LABEL : Cell Value, String Constant - ajjHRW len=0 
' 0018     24 LABEL : Cell Value, String Constant - akhnCAzMw len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!E185 
' 0018     23 LABEL : Cell Value, String Constant - axYNHQhi len=0 
' 0018     20 LABEL : Cell Value, String Constant - bXnRE len=0 
' 0018     26 LABEL : Cell Value, String Constant - ddBNCNYhLUN len=0 
' 0018     27 LABEL : Cell Value, String Constant - dpEUPVrwVnxm len=0 
' 0018     21 LABEL : Cell Value, String Constant - eJkRAE len=0 
' 0018     24 LABEL : Cell Value, String Constant - gkXKjXMYF len=0 
' 0018     27 LABEL : Cell Value, String Constant - havMVWxogRte len=0 
' 0018     24 LABEL : Cell Value, String Constant - JMhrJKwYw len=0 
' 0018     21 LABEL : Cell Value, String Constant - KezFWu len=0 
' 0018     26 LABEL : Cell Value, String Constant - MNHKgbiLRyu len=0 
' 0018     22 LABEL : Cell Value, String Constant - oggFFvK len=0 
' 0018     26 LABEL : Cell Value, String Constant - parZQVjOnDY len=0 
' 0018     22 LABEL : Cell Value, String Constant - sjxxdhL len=0 
' 0018     20 LABEL : Cell Value, String Constant - styKP len=0 
' 0018     21 LABEL : Cell Value, String Constant - UemMXG len=0 
' 0018     27 LABEL : Cell Value, String Constant - UIdTiJmBLrLz len=0 
' 0018     23 LABEL : Cell Value, String Constant - YeLQeEJy len=0 
' 0018     22 LABEL : Cell Value, String Constant - ZJzrnnX 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    
... (truncated)

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