Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 0e3e547a25bd4c21…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:43:06 Authoring application: Microsoft Excel First seen: 2021-06-28
MD5: 6afc511095a0904ce937d37fff25b1c5 SHA-1: 238fa60ebd42bdb64fd9697baeff5a938a13b719 SHA-256: 0e3e547a25bd4c21f70b072d6c83d23577fae6c4ea639c2351a09ffcd68b490c
140 Risk Score

Malware Insights

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

The sample is an Excel file containing Excel 4.0 macros, specifically an Auto_Open macro. This macro is designed to execute dangerous formula APIs, including the RUN function, which is highly indicative of an attempt to download and execute a secondary payload. The presence of the Auto_Open entry and the use of the RUN function strongly suggest a malicious intent to compromise the user's system.

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) 6872 bytes
SHA-256: 551cd9464b0638224fb32a22a3c41feee9141365a460976a421dc7da170ca9b1
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     19 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  cKClAoRHRB
' 0018     27 LABEL : Cell Value, String Constant - adNfjMWstths len=0 
' 0018     22 LABEL : Cell Value, String Constant - asMfNBV len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!C165 
' 0018     22 LABEL : Cell Value, String Constant - dMftxDY len=0 
' 0018     22 LABEL : Cell Value, String Constant - GAryvqJ len=0 
' 0018     22 LABEL : Cell Value, String Constant - jAUicmp len=0 
' 0018     26 LABEL : Cell Value, String Constant - JFhKtBwvenW len=0 
' 0018     27 LABEL : Cell Value, String Constant - kCBzBbsLWkXz len=0 
' 0018     20 LABEL : Cell Value, String Constant - OOQSp len=0 
' 0018     27 LABEL : Cell Value, String Constant - pzaWuLvXfikI len=0 
' 0018     21 LABEL : Cell Value, String Constant - QDwvhi len=0 
' 0018     23 LABEL : Cell Value, String Constant - SBWhGEeU len=0 
' 0018     20 LABEL : Cell Value, String Constant - sNNVp len=0 
' 0018     21 LABEL : Cell Value, String Constant - SPAvpr len=0 
' 0018     26 LABEL : Cell Value, String Constant - UdAyTrCXwdN len=0 
' 0018     26 LABEL : Cell Value, String Constant - uJkzfpFKETM len=0 
' 0018     27 LABEL : Cell Value, String Constant - VvdGavgrlrRX len=0 
' 0018     26 LABEL : Cell Value, String Constant - vvsLUwQutfm len=0 
' 0018     25 LABEL : Cell Value, String Constant - wdsWldorUf len=0 
' 0018     27 LABEL : Cell Value, String Constant - WmOEbCeKElEr len=0 
' 0018     24 LABEL : Cell Value, String Constant - YTYXIBxDB 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/
... (truncated)