Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 279df28cdbde6c14…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:46:28 Authoring application: Microsoft Excel First seen: 2021-07-13
MD5: 0b7178ddc60b4d445192fb389f25a8b0 SHA-1: 51e574cee556b9af70e8fffbaa4fdab6d56ddea2 SHA-256: 279df28cdbde6c147bbb7d7e82391f118f7f45e6720c3b14dd4dd6729e05c1dd
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 defined name, indicating it will execute code upon opening. Heuristics indicate the use of dangerous formula APIs, specifically 'RUN=0', suggesting the macro is designed to execute an external program or payload. The extensive obfuscated strings in the document body further support the malicious intent, likely for a downloader or initial access vector.

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) 6719 bytes
SHA-256: 7eec7ad1d0894f88c1fc90d88c56acf4dbf0c3281486014f3e3d96838c4a40f7
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     16 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  AxxvVQk
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!E186 
' 0018     21 LABEL : Cell Value, String Constant - aWyoHC len=0 
' 0018     20 LABEL : Cell Value, String Constant - cuMFN len=0 
' 0018     24 LABEL : Cell Value, String Constant - czddhtMiw len=0 
' 0018     22 LABEL : Cell Value, String Constant - dLAknfx len=0 
' 0018     22 LABEL : Cell Value, String Constant - GGoxirf len=0 
' 0018     22 LABEL : Cell Value, String Constant - kGjshYQ len=0 
' 0018     25 LABEL : Cell Value, String Constant - KKdxnqMbXn len=0 
' 0018     26 LABEL : Cell Value, String Constant - kxyoZUNcXSQ len=0 
' 0018     21 LABEL : Cell Value, String Constant - LatEIw len=0 
' 0018     21 LABEL : Cell Value, String Constant - lzgwEb len=0 
' 0018     20 LABEL : Cell Value, String Constant - MzcbI len=0 
' 0018     27 LABEL : Cell Value, String Constant - napFYcFxNGZL len=0 
' 0018     23 LABEL : Cell Value, String Constant - nHyxUuht len=0 
' 0018     26 LABEL : Cell Value, String Constant - OIVJUnHtYXo len=0 
' 0018     23 LABEL : Cell Value, String Constant - OSczaPMk len=0 
' 0018     26 LABEL : Cell Value, String Constant - uUjqIEzCbVb len=0 
' 0018     22 LABEL : Cell Value, String Constant - vsaMTXz len=0 
' 0018     25 LABEL : Cell Value, String Constant - XMtrXZGlWM len=0 
' 0018     27 LABEL : Cell Value, String Constant - yCaVOxUnRCVb len=0 
' 0018     23 LABEL : Cell Value, String Constant - yGcQRPqn 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
... (truncated)

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