Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b40cd7e10bba08a3…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:44:39 Authoring application: Microsoft Excel First seen: 2021-06-13
MD5: acde9e94d587bde4f4a72938d838004d SHA-1: af17795a527da77d83712714247dd9e9f3a37cdf SHA-256: b40cd7e10bba08a3afa4b076bbe1190a191c69055b8606ff403e01a653122912
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 sheet containing an Auto_Open function, which is a common technique for executing malicious code upon opening the workbook. The critical heuristic firings indicate the presence of dangerous formula APIs within the Auto_Open macro, suggesting it is designed to perform harmful actions. No specific IOCs like URLs or hashes were extracted, but the technique itself is highly suspicious.

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) 6826 bytes
SHA-256: 8de066b70f447d60713e23154f81b02e492af0072bed017c28b6e2600b02e51a
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 -  RCiCfhfxG
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!A151 
' 0018     21 LABEL : Cell Value, String Constant - CrnXEO len=0 
' 0018     24 LABEL : Cell Value, String Constant - dADwkuapk len=0 
' 0018     27 LABEL : Cell Value, String Constant - FZdMeABkHBVH len=0 
' 0018     21 LABEL : Cell Value, String Constant - hcoUBe len=0 
' 0018     27 LABEL : Cell Value, String Constant - JtxRiHrqVCmK len=0 
' 0018     26 LABEL : Cell Value, String Constant - kgeimfWUFRx len=0 
' 0018     26 LABEL : Cell Value, String Constant - KKwlGOEEaJt len=0 
' 0018     23 LABEL : Cell Value, String Constant - ktQmlmMq len=0 
' 0018     23 LABEL : Cell Value, String Constant - mgGYIIAb len=0 
' 0018     24 LABEL : Cell Value, String Constant - PurUhbecd len=0 
' 0018     27 LABEL : Cell Value, String Constant - QTYYPadoRnzk len=0 
' 0018     24 LABEL : Cell Value, String Constant - TeqSaccax len=0 
' 0018     25 LABEL : Cell Value, String Constant - tNAyPwxIwV len=0 
' 0018     20 LABEL : Cell Value, String Constant - tzdaw len=0 
' 0018     26 LABEL : Cell Value, String Constant - UDLUBMHyuDc len=0 
' 0018     20 LABEL : Cell Value, String Constant - utvXl len=0 
' 0018     26 LABEL : Cell Value, String Constant - xMFtCPByCWx len=0 
' 0018     26 LABEL : Cell Value, String Constant - YQjrxYeUNeq len=0 
' 0018     24 LABEL : Cell Value, String Constant - ZFnaDVUcR len=0 
' 0018     26 LABEL : Cell Value, String Constant - ztiwABMrppD 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 Const
... (truncated)

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