Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 812145d9b2b406b3…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:46:49 Authoring application: Microsoft Excel First seen: 2021-06-13
MD5: 9e19884c8998f998d380da8541fea93e SHA-1: 9862f98a4b2d4c7432bb6f2f936cf7b92c5a6f63 SHA-256: 812145d9b2b406b3698f54a961fa07dfdf6041802aa8161823faeeec6f9c7f03
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. Heuristics indicate the presence of an Auto_Open macro, which is a common technique for executing malicious code upon opening the document. The macro sheet contains references to dangerous formula APIs, including RUN, suggesting it is designed to execute arbitrary commands. This functionality is likely used to download and execute a second-stage 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) 6399 bytes
SHA-256: 908939abe98a8b9e704112ab41a888497a5af0d054826eeec61ddaf4c4d2cdb8
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     13 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  rxpZ
' 0018     27 LABEL : Cell Value, String Constant - aJxqrcLPWUDo len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!E165 
' 0018     20 LABEL : Cell Value, String Constant - BzjZI len=0 
' 0018     25 LABEL : Cell Value, String Constant - esUOBDeWly len=0 
' 0018     25 LABEL : Cell Value, String Constant - FkQZrTwlCQ len=0 
' 0018     20 LABEL : Cell Value, String Constant - FScyQ len=0 
' 0018     21 LABEL : Cell Value, String Constant - FUFDjX len=0 
' 0018     20 LABEL : Cell Value, String Constant - gxRmK len=0 
' 0018     27 LABEL : Cell Value, String Constant - IdmhbwnnnkSa len=0 
' 0018     20 LABEL : Cell Value, String Constant - jdEKF len=0 
' 0018     24 LABEL : Cell Value, String Constant - jSPXvvwCb len=0 
' 0018     26 LABEL : Cell Value, String Constant - KllOUAPoCIu len=0 
' 0018     26 LABEL : Cell Value, String Constant - ljBmhqTuJDE len=0 
' 0018     23 LABEL : Cell Value, String Constant - LZSjzyNq len=0 
' 0018     23 LABEL : Cell Value, String Constant - NlJHoCtc len=0 
' 0018     21 LABEL : Cell Value, String Constant - PdPSGH len=0 
' 0018     26 LABEL : Cell Value, String Constant - sNeJBGCaCdp len=0 
' 0018     23 LABEL : Cell Value, String Constant - UQIJiwXL len=0 
' 0018     24 LABEL : Cell Value, String Constant - vkOWoTosl len=0 
' 0018     24 LABEL : Cell Value, String Constant - XAVbYmaBr len=0 
' 0018     20 LABEL : Cell Value, String Constant - zfhEd 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 LAB
... (truncated)

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