Linux glibc ghost vulnerability repair method, linuxglibc ghost Vulnerability

Linux glibc ghost vulnerability repair method, linuxglibc ghost Vulnerability

I will not talk about this vulnerability here. For more information, click the connection below.

CVE-2015-0235: Linux Glibc ghost vulnerability allows hackers to remotely obtain SYSTEM privileges

Test whether the vulnerability exists:

Save the following code as gistfile1.c

#include <netdb.h>#include <stdio.h>#include <stdlib.h>#include <string.h>#include <errno.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);}#* from http://www.openwall.com/lists/oss-security/2015/01/27/9 */

Then run the following command on the server:

 gcc gistfile1.c -o CVE-2015-0235 ./CVE-2015-0235

If the message "vulnerable" is displayed, the vulnerability exists.

Solution:

Run these commands.

yum clean all yum makecacheyum -y install glibc*