Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 2815fff76bf24d66…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:39:54 Authoring application: Microsoft Excel First seen: 2021-07-10
MD5: e784a74bcc16fe3bf32ca9d976c0e0c4 SHA-1: 4b8a7707c8375a34bf183858cce963bc2a8fe07b SHA-256: 2815fff76bf24d6683d6ed3d278fe89a7e916b9236cf9edaf7b6e7c0fd7fe7ec
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding indicating potential malicious execution. The presence of dangerous formula APIs like RUN further supports this. While the exact payload is not discernible from the provided evidence, the Auto_Open macro is designed to execute code upon opening the workbook, likely leading to further compromise.

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) 6843 bytes
SHA-256: c95ffbba23084e05e1712f365189ef46e8842985b24128a374379fbd15ac7ac1
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 -  HmMfklWtJ
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!C145 
' 0018     26 LABEL : Cell Value, String Constant - cKPwgUXGfcR len=0 
' 0018     20 LABEL : Cell Value, String Constant - cNiCs len=0 
' 0018     20 LABEL : Cell Value, String Constant - FRGCa len=0 
' 0018     25 LABEL : Cell Value, String Constant - InyLmbbdiV len=0 
' 0018     25 LABEL : Cell Value, String Constant - ixEJiLWbjY len=0 
' 0018     22 LABEL : Cell Value, String Constant - jYzgmgW len=0 
' 0018     25 LABEL : Cell Value, String Constant - kfcBwNqmYk len=0 
' 0018     20 LABEL : Cell Value, String Constant - lakhn len=0 
' 0018     20 LABEL : Cell Value, String Constant - NjkGM len=0 
' 0018     22 LABEL : Cell Value, String Constant - PtnlsRt len=0 
' 0018     23 LABEL : Cell Value, String Constant - smnEWcHy len=0 
' 0018     27 LABEL : Cell Value, String Constant - soZIpCLqaYbL len=0 
' 0018     23 LABEL : Cell Value, String Constant - TknUMCzS len=0 
' 0018     27 LABEL : Cell Value, String Constant - UCZpeYZcRhQR len=0 
' 0018     24 LABEL : Cell Value, String Constant - UsnmpTVge len=0 
' 0018     26 LABEL : Cell Value, String Constant - VMTEBnRGHVS len=0 
' 0018     22 LABEL : Cell Value, String Constant - XkPsIuz len=0 
' 0018     23 LABEL : Cell Value, String Constant - YlMzpwHB len=0 
' 0018     26 LABEL : Cell Value, String Constant - ZCEwzmXuxrI len=0 
' 0018     21 LABEL : Cell Value, String Constant - zsSONA 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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