Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 59c7d9e1997398e0…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:46:54 Authoring application: Microsoft Excel First seen: 2021-07-10
MD5: e29644ce5bf17011688b035e3082bed3 SHA-1: f5ed6d6f2acf26c81556fee33fb8873ac248e759 SHA-256: 59c7d9e1997398e0f954fd3a6b0c12147c8b003e76ee9491413606bd9a02df58
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 containing an Auto_Open function, which is a critical indicator of malicious intent. This function is designed to execute arbitrary code upon opening the workbook, likely to download and execute a second-stage payload. The presence of dangerous formula APIs further supports this assessment.

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) 6641 bytes
SHA-256: 2bb24858d6fdea29743eabfc0ae5cd2509bf0a8b64cfd3d6530af654d680f505
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 -  MgFOm
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!E164 
' 0018     26 LABEL : Cell Value, String Constant - BgtuLPtcbGZ len=0 
' 0018     21 LABEL : Cell Value, String Constant - CEtlYc len=0 
' 0018     20 LABEL : Cell Value, String Constant - DjPwV len=0 
' 0018     26 LABEL : Cell Value, String Constant - esMfQqUqufp len=0 
' 0018     24 LABEL : Cell Value, String Constant - fppcQZfqQ len=0 
' 0018     22 LABEL : Cell Value, String Constant - HtkkhHM len=0 
' 0018     22 LABEL : Cell Value, String Constant - ihHwwDW len=0 
' 0018     25 LABEL : Cell Value, String Constant - JSMhARRNbd len=0 
' 0018     27 LABEL : Cell Value, String Constant - NixfHVcpTwUO len=0 
' 0018     20 LABEL : Cell Value, String Constant - pfefe len=0 
' 0018     24 LABEL : Cell Value, String Constant - pkCexhlKA len=0 
' 0018     26 LABEL : Cell Value, String Constant - QvZJwfncDuH len=0 
' 0018     26 LABEL : Cell Value, String Constant - rdrrGgVTMGO len=0 
' 0018     26 LABEL : Cell Value, String Constant - sBRTXnwGmMZ len=0 
' 0018     21 LABEL : Cell Value, String Constant - sKClbp len=0 
' 0018     25 LABEL : Cell Value, String Constant - tISTwwYlFU len=0 
' 0018     21 LABEL : Cell Value, String Constant - tlsFQu len=0 
' 0018     24 LABEL : Cell Value, String Constant - uhOurdxcf len=0 
' 0018     27 LABEL : Cell Value, String Constant - VbWASMFTFuKK len=0 
' 0018     27 LABEL : Cell Value, String Constant - WVjBTGfVexKB 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
'
... (truncated)

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