glibc(CVE-2015-0235) 最新漏洞解决方法

January 28, 2015CommentsRead

幽灵漏洞是Linux glibc库上出现的一个严重的安全问题，他可以让攻击者在不了解系统的任何情况下远程获取操作系统的控制权限。目前他的CVE编号为CVE-2015-0235。

修复方法：
Centos 5/6/7：

yum update glibc

0	yum update glibc

Ubuntu 12/14:

apt-get update 
apt-get install libc6

0 1	apt-get update apt-get install libc6

Debian 6:

wget -O /etc/apt/sources.list.d/debian6-lts.list http://mirrors.aliyun.com/repo/debian6-lts.list 
apt-get update 
apt-get install libc6

wget -O /etc/apt/sources.list.d/debian6-lts.list http://mirrors.aliyun.com/repo/debian6-lts.list

apt-get update

apt-get install libc6

Debian 7:

apt-get update 
apt-get install libc6

0 1	apt-get update apt-get install libc6

Opensuse 13

zypper refresh 
zypper update glibc*

0 1	zypper refresh zypper update glibc*

漏洞概述文章源自 note.t4x.orgByrd's Blog-https://note.t4x.org/environment/fix-glibc-bug/

代码审计公司Qualys的研究人员在glibc库中的__nss_hostname_digits_dots()函数中发现了一个缓冲区溢出的漏洞，这个bug可以经过gethostbyname*()函数被本地或者远程的触发。文章源自 note.t4x.orgByrd's Blog-https://note.t4x.org/environment/fix-glibc-bug/

应用程序主要使用gethostbyname*()函数发起DNS请求，这个函数会将主机名称转换为ip地址。

什么是glibc文章源自 note.t4x.orgByrd's Blog-https://note.t4x.org/environment/fix-glibc-bug/

glibc是GNU发布的libc库，即c运行库。glibc是linux系统中最底层的api，几乎其它任何运行库都会依赖于glibc。glibc除了封装linux操作系统所提供的系统服务外，它本身也提供了许多其它一些必要功能服务的实现。glibc囊括了几乎所有的UNIX通行的标准。文章源自 note.t4x.orgByrd's Blog-https://note.t4x.org/environment/fix-glibc-bug/

影响范围文章源自 note.t4x.orgByrd's Blog-https://note.t4x.org/environment/fix-glibc-bug/

该漏洞影响glibc库版本2.2-2.17的Linux操作系统

操作系统类型包括

CentOS 6 & 7
Debian 7
Red Hat Enterprise Linux 6 & 7
Ubuntu 10.04 & 12.04
各Linux发行版

CentOS 6 & 7

Debian 7

Red Hat Enterprise Linux 6 & 7

Ubuntu 10.04 & 12.04

各Linux发行版

测试：

[root@qd tmp]# cat /etc/redhat-release 
CentOS Linux release 7.0.1406 (Core) 
[root@qd tmp]# gcc 1.c -o byrd 
[root@qd tmp]# ./byrd           
vulnerable
[root@qd tmp]# cat 1.c 
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <gnu/libc-version.h>
#define CANARY "in_the_coal_mine"
struct {
char buffer[1024];
char canary[sizeof(CANARY)];
} temp = { "buffer", CANARY };
int main(void) {
struct hostent resbuf;
struct hostent *result;
int herrno;
int retval;
/*** strlen (name) = size_needed - sizeof (*host_addr) - sizeof (*h_addr_ptrs) - 1; ***/
size_t len = sizeof(temp.buffer) - 16*sizeof(unsigned char) - 2*sizeof(char *) - 1;
char name[sizeof(temp.buffer)];
memset(name, '0', len);
name[len] = '\0';
retval = gethostbyname_r(name, &resbuf, temp.buffer, sizeof(temp.buffer), &result, &herrno);
if (strcmp(temp.canary, CANARY) != 0) {
puts("vulnerable");
exit(EXIT_SUCCESS);
}
if (retval == ERANGE) {
puts("not vulnerable");
exit(EXIT_SUCCESS);
}
puts("should not happen");
exit(EXIT_FAILURE);
}
[root@qd tmp]# yum install glibc -y #fix

[root@qd tmp]# cat /etc/redhat-release

CentOS Linux release 7.0.1406 (Core)

[root@qd tmp]# gcc 1.c -o byrd

[root@qd tmp]# ./byrd

vulnerable

[root@qd tmp]# cat 1.c

#include <netdb.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <errno.h>

#include <gnu/libc-version.h>

#define CANARY "in_the_coal_mine"

struct {

char buffer[1024];

char canary[sizeof(CANARY)];

} temp = { "buffer", CANARY };

int main(void) {

struct hostent resbuf;

struct hostent *result;

int herrno;

int retval;

/*** strlen (name) = size_needed - sizeof (*host_addr) - sizeof (*h_addr_ptrs) - 1; ***/

size_t len = sizeof(temp.buffer) - 16*sizeof(unsigned char) - 2*sizeof(char *) - 1;

char name[sizeof(temp.buffer)];

memset(name, '0', len);

name[len] = '\0';

retval = gethostbyname_r(name, &resbuf, temp.buffer, sizeof(temp.buffer), &result, &herrno);

if (strcmp(temp.canary, CANARY) != 0) {

puts("vulnerable");

exit(EXIT_SUCCESS);

}

if (retval == ERANGE) {

puts("not vulnerable");

exit(EXIT_SUCCESS);

}

puts("should not happen");

exit(EXIT_FAILURE);

}

[root@qd tmp]# yum install glibc -y #fix

文章源自 note.t4x.orgByrd's Blog-https://note.t4x.org/environment/fix-glibc-bug/

转载：https://threatpost.com/ghost-glibc-remote-code-execution-vulnerability-affects-all-linux-systems/110679
转载：http://www.freebuf.com/news/57729.html文章源自 note.t4x.orgByrd's Blog-https://note.t4x.org/environment/fix-glibc-bug/ 文章源自 note.t4x.orgByrd's Blog-https://note.t4x.org/environment/fix-glibc-bug/

申明：除非注明Byrd's Blog内容均为原创,未经许可禁止转载!详情请阅读版权申明!

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