Re: sample buffer overflow exploit problem

["sohlow" <sohlow () hushmail com>]

> Is there anyway I can generate shellcodes in FreeBSD?

a good tute to check out [for bsd/unix asm development] is at
http://www.int80h.org/bsdasm/

next thing you'd need to do is find a list of the syscalls you
wanna use. use the src as a last resort.

sohlow

> From: Ganbold <ganbold () micom mng net>
> To: vuln-dev () securityfocus com
> Subject: sample buffer overflow exploit problem
> Date: Sat, 27 Sep 2003 16:54:59 +0900
>
> Hi,
>
> I'm very new to buffer overflow exploit technics and my boss wants me
to 
> thoroughly understand
> how it works. I'm trying to exploit sample network server in FreeBSD
5.1 
> for this purpose.
> When I try to exploit using execve /bin/sh (shellcode1), it works and

> launches the shell in the remote machine.
> However when I try to use port binding shell code, it binds shell to
the 
> port, but when I try to connect to
> it, it just closes the connection. Also I can't connect to bind port
after 
> sending buffer using following code snippets:
> ..............
>       printf("[-] Connecting to bindshell...\n");
>       remote.sin_family = AF_INET;
>       remote.sin_addr = *((struct in_addr *)host->h_addr);
>       remote.sin_port = htons(12345);
>       if (connect(s, (struct sockaddr *)&remote, sizeof(remote))==-1)
>       {
>               close(s);
>               fprintf(stderr, "Error: connect\n");
>               return -1;
>       }
>       exec_sh(s);
> ...............
>
> I appreciate if somebody give me some help to solve this test problem.
> Is there anywhere I can find detailed explanation about buffer overflows

> and working sample network exploits?
> Is there anyway I can generate shellcodes in FreeBSD?
>
> I attached my sample server code and exploit code.
>
> thanks in advance,
>
> Ganbold Ts,
>
> senior programmer,
> Micom Co., Ltd
> Ulaanbaatar,
> Mongolia



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