Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b1efd9a3857ee74b…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-25 10:47:14 Authoring application: Microsoft Excel First seen: 2021-09-27
MD5: bc374e1edcd5a48afbf45556d832098c SHA-1: ee231f49089ff9daed394efa3b34555ff087b456 SHA-256: b1efd9a3857ee74b709136c3c9c1ea4fc0e509a72e178bde48e0cd4a1a804f6e
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 that contains an Auto_Open defined name, indicating that macros will execute automatically upon opening. Heuristics indicate the use of dangerous formula APIs, specifically referencing 'RUN=0', suggesting the execution of arbitrary commands or payloads. The presence of an Auto_Open entry and the use of dangerous functions strongly suggest an attempt to execute malicious code.

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) 6634 bytes
SHA-256: 63ed9dfcdf56d5ab4b9f6e7c01a5a7d856a69b51211ee623c582fb3a39a74f99
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     17 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  cYVgjKuv
' 0018     21 LABEL : Cell Value, String Constant - AmENqL len=0 
' 0018     22 LABEL : Cell Value, String Constant - aPRULOP len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!D142 
' 0018     20 LABEL : Cell Value, String Constant - ccpLy len=0 
' 0018     20 LABEL : Cell Value, String Constant - DbHlN len=0 
' 0018     25 LABEL : Cell Value, String Constant - dbrlAMlxnr len=0 
' 0018     20 LABEL : Cell Value, String Constant - iCrgo len=0 
' 0018     24 LABEL : Cell Value, String Constant - itZKvinfD len=0 
' 0018     25 LABEL : Cell Value, String Constant - jUDzYbiRDe len=0 
' 0018     27 LABEL : Cell Value, String Constant - kSwuPoQVWouE len=0 
' 0018     22 LABEL : Cell Value, String Constant - LDRucLT len=0 
' 0018     27 LABEL : Cell Value, String Constant - lkBHNFWLhjPp len=0 
' 0018     24 LABEL : Cell Value, String Constant - lvJlpwCzZ len=0 
' 0018     24 LABEL : Cell Value, String Constant - RCMZQpyWR len=0 
' 0018     21 LABEL : Cell Value, String Constant - Tncglx len=0 
' 0018     23 LABEL : Cell Value, String Constant - uCwOCOCM len=0 
' 0018     27 LABEL : Cell Value, String Constant - UyKdiRBtMlRr len=0 
' 0018     20 LABEL : Cell Value, String Constant - vKkfJ len=0 
' 0018     25 LABEL : Cell Value, String Constant - vYVENnZbDx len=0 
' 0018     23 LABEL : Cell Value, String Constant - WUGAjrkf len=0 
' 0018     21 LABEL : Cell Value, String Constant - ZQcEJZ 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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