Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 797aa44d59ac6d3e…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:28:06 Authoring application: Microsoft Excel First seen: 2021-07-02
MD5: 1f8edaf6f295eec1944a06783d67546f SHA-1: ea00ddbfca4b7abc56b8bda13bc89180ec9c3c2f SHA-256: 797aa44d59ac6d3e5eba715c74a615321ac5e4753a6a9ec7b91a1797016c9c83
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file is an Excel macro-enabled document containing Excel 4.0 (XLM) macros. Critical heuristics indicate the presence of an Auto_Open defined name and the use of dangerous formula APIs, specifically the RUN function, which is commonly used to execute arbitrary commands. This suggests the macro is designed 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) 6622 bytes
SHA-256: 8c6d5ff559a24b5def8eab32002e49a7560b7de18d69cc38a5fb91308118436d
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     20 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  cPmboGleSKR
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!D157 
' 0018     24 LABEL : Cell Value, String Constant - bVXrcdXGe len=0 
' 0018     26 LABEL : Cell Value, String Constant - CuUpfspDlbO len=0 
' 0018     26 LABEL : Cell Value, String Constant - DwDSCjALIRF len=0 
' 0018     20 LABEL : Cell Value, String Constant - jgzuR len=0 
' 0018     21 LABEL : Cell Value, String Constant - jxcTkO len=0 
' 0018     26 LABEL : Cell Value, String Constant - kMqZGYbXpjr len=0 
' 0018     26 LABEL : Cell Value, String Constant - mpMYbItMbKJ len=0 
' 0018     23 LABEL : Cell Value, String Constant - MRvvOxNm len=0 
' 0018     24 LABEL : Cell Value, String Constant - NZPmNzeFA len=0 
' 0018     25 LABEL : Cell Value, String Constant - oTkYxasROQ len=0 
' 0018     21 LABEL : Cell Value, String Constant - PkKDCm len=0 
' 0018     24 LABEL : Cell Value, String Constant - QRjPsaQeT len=0 
' 0018     24 LABEL : Cell Value, String Constant - rguRLctlj len=0 
' 0018     22 LABEL : Cell Value, String Constant - SMIYmWg len=0 
' 0018     22 LABEL : Cell Value, String Constant - WHofvUd len=0 
' 0018     21 LABEL : Cell Value, String Constant - wiJdWp len=0 
' 0018     27 LABEL : Cell Value, String Constant - wqPbxMFlTnqA len=0 
' 0018     21 LABEL : Cell Value, String Constant - XUTarF len=0 
' 0018     21 LABEL : Cell Value, String Constant - ZhWZTU len=0 
' 0018     21 LABEL : Cell Value, String Constant - ZupMPS 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)