Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 da46b1efb2c0e39c…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:38:55 Authoring application: Microsoft Excel First seen: 2021-10-16
MD5: 2852e49fb0830f36e3d65d0e00987a41 SHA-1: 9354b2cb68e4d0087f679a62acde4fbed99b71d3 SHA-256: da46b1efb2c0e39ce1d94ca36322a3ce88d7a67abe0687df491098fe8c390a5e
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 detected with critical heuristics indicating the presence of an Auto_Open macro. This macro is configured to execute dangerous formula APIs, specifically identified as 'RUN=0', which is commonly used to download and execute arbitrary code. The macro sheet contains numerous obfuscated string constants, suggesting an attempt to hide the payload or its download URL.

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) 6462 bytes
SHA-256: 1a6b895d1bb449f332ef5e5aef3690167ffa9773a6b8e504666642e35a8f85ba
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     14 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  PijyZ
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!I166 
' 0018     20 LABEL : Cell Value, String Constant - awtjJ len=0 
' 0018     22 LABEL : Cell Value, String Constant - axTlsxe len=0 
' 0018     26 LABEL : Cell Value, String Constant - BpYdaodNwBv len=0 
' 0018     27 LABEL : Cell Value, String Constant - BQtxdfXZgJdT len=0 
' 0018     24 LABEL : Cell Value, String Constant - diRAlbAvz len=0 
' 0018     24 LABEL : Cell Value, String Constant - gIBtIgPIW len=0 
' 0018     27 LABEL : Cell Value, String Constant - JdFcuIaXmyTE len=0 
' 0018     21 LABEL : Cell Value, String Constant - JSowjk len=0 
' 0018     26 LABEL : Cell Value, String Constant - KvvIormwFwj len=0 
' 0018     22 LABEL : Cell Value, String Constant - lHXFTjb len=0 
' 0018     22 LABEL : Cell Value, String Constant - LLRRnkU len=0 
' 0018     27 LABEL : Cell Value, String Constant - OiEaXoSeMisH len=0 
' 0018     23 LABEL : Cell Value, String Constant - pAVBLXrn len=0 
' 0018     22 LABEL : Cell Value, String Constant - RVskolX len=0 
' 0018     22 LABEL : Cell Value, String Constant - sRrWIZG len=0 
' 0018     26 LABEL : Cell Value, String Constant - TKanVjswJmS len=0 
' 0018     22 LABEL : Cell Value, String Constant - VpLbmrO len=0 
' 0018     22 LABEL : Cell Value, String Constant - xOcJyWJ len=0 
' 0018     27 LABEL : Cell Value, String Constant - ZDcohdnkwQRp len=0 
' 0018     20 LABEL : Cell Value, String Constant - zVmqQ 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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