Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 a300ca2fef9f747d…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:45:15 Authoring application: Microsoft Excel First seen: 2021-09-18
MD5: ff04447e15aaa53e27126b353c56a061 SHA-1: 16163db7bbe8e9a0bd371289b0d3f2b58f890bc6 SHA-256: a300ca2fef9f747d73239e0717bf797d51b73030883428ce7d86baa3627c63c5
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-enabled workbook. Static analysis identified an Auto_Open defined name and the use of dangerous formula APIs, specifically the RUN function, indicating an intent to execute arbitrary code upon opening. The macro sheet itself contains obfuscated strings and appears to be designed 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) 6752 bytes
SHA-256: c14c8984cbf0c412b8dc107f7fac757c3cd7aa06bf9705c688d9ca33adbc2cef
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 -  smHlCo
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!D177 
' 0018     23 LABEL : Cell Value, String Constant - BMotTyfy len=0 
' 0018     23 LABEL : Cell Value, String Constant - CWPiDaVN len=0 
' 0018     23 LABEL : Cell Value, String Constant - doWrgzjm len=0 
' 0018     20 LABEL : Cell Value, String Constant - EEhNv len=0 
' 0018     26 LABEL : Cell Value, String Constant - EMqBbxWStAd len=0 
' 0018     20 LABEL : Cell Value, String Constant - emYKQ len=0 
' 0018     26 LABEL : Cell Value, String Constant - fOGGDCTgvJC len=0 
' 0018     23 LABEL : Cell Value, String Constant - fvCWxcRP len=0 
' 0018     25 LABEL : Cell Value, String Constant - gJzCZHAXqL len=0 
' 0018     26 LABEL : Cell Value, String Constant - INJsysfMMYf len=0 
' 0018     20 LABEL : Cell Value, String Constant - JzcZm len=0 
' 0018     26 LABEL : Cell Value, String Constant - KhYfKDdCjfL len=0 
' 0018     26 LABEL : Cell Value, String Constant - KiaUuTdXGQC len=0 
' 0018     25 LABEL : Cell Value, String Constant - kUYLiNNlbh len=0 
' 0018     22 LABEL : Cell Value, String Constant - SElFaqw len=0 
' 0018     26 LABEL : Cell Value, String Constant - tBwBIlTOBAp len=0 
' 0018     25 LABEL : Cell Value, String Constant - VASqocQUBQ len=0 
' 0018     26 LABEL : Cell Value, String Constant - YhmythbqJLj len=0 
' 0018     22 LABEL : Cell Value, String Constant - YnsCVdO len=0 
' 0018     25 LABEL : Cell Value, String Constant - YOMSudYtTs 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
' 
... (truncated)

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