GHOST - Revision history

Lucas Trottier: Change enumeration for numerated list

2015-07-20T15:28:01Z

Change enumeration for numerated list

Candy Chan: Added the timezone reset procedures

2015-02-18T05:24:56Z

Added the timezone reset procedures

Atremblay: /* WebPortal - TMG unit or Linux server with access to Internet (i.e. with DNS configured) */

2015-02-03T15:49:06Z

WebPortal - TMG unit or Linux server with access to Internet (i.e. with DNS configured)

Atremblay: Updated with reboot

2015-02-03T15:29:13Z

Updated with reboot

Cboulanger: Added the possibility to update through the WebPortal

2015-02-03T15:09:07Z

Added the possibility to update through the WebPortal

Atremblay: Fixed vulnerability script

2015-02-03T14:56:15Z

Fixed vulnerability script

Atremblay: Initial page

2015-02-03T14:28:23Z

Initial page

New page

{{DISPLAYTITLE:GHOST: The glibc's gethostbyname vulnerability}}

On January 27, 2015, a vulnerability named "GHOST" in the glibc library was publicly announced. GHOST is also referred as '''CVE-2015-0235'''. The vulnerability is a buffer overflow in the gethostbyname family of functions that can allow arbitrary code execution.

= Affected Products =
* TMG800, TMG3200, TMG7800-CTRL
* Tdev Linux server with (CentOS, RedHat, etc) running Toolpack software

= Details =
The impact of this vulnerability on TelcoBridges products depends on their configuration. The vulnerability may only be triggered through requests for domain name resolution. Therefore, only units that enable such services may be exposed to the issue.

= Software Versions and Fixes =
The TelcoBridges CentOS 5 repository has been updated with the latest glibc version. Services that use glibc must be restarted. Because glibc is thoroughly used in the Linux operating system, it is highly recommended to reboot the unit.

= Update procedure =
* login with root account
[root@TB011107 ~]# uname -m
x86_64
* If the result is not "x86_64", [[Support:Contacting TelcoBridges technical support|please contact TelcoBridges]] support, otherwise you can proceed with either method below.

== Command line interface - TMG unit or Linux server '''with access to Internet''' (i.e. with DNS configured) ==
* login with root account
* update OS packages with yum
yum clean all
yum update
* reboot the unit
reboot

== TMG unit or Linux server '''without access to Internet''' ==
* download the following packages to your PC:
** http://repo.telcobridges.com/centos/5.7/updates/x86_64/RPMS/glibc-2.5-123.el5_11.1.x86_64.rpm
** http://repo.telcobridges.com/centos/5.7/updates/x86_64/RPMS/glibc-common-2.5-123.el5_11.1.x86_64.rpm
** http://repo.telcobridges.com/centos/5.7/updates/x86_64/RPMS/glibc-devel-2.5-123.el5_11.1.x86_64.rpm
** http://repo.telcobridges.com/centos/5.7/updates/x86_64/RPMS/glibc-headers-2.5-123.el5_11.1.x86_64.rpm
** http://repo.telcobridges.com/centos/5.7/updates/x86_64/RPMS/nscd-2.5-123.el5_11.1.x86_64.rpm
* Using WinSCP or similar tool, upload the files to the TMG unit using the root account
* login with root account
* Install packages
yum localinstall glibc-2.5-123.el5_11.1.x86_64.rpm \
glibc-common-2.5-123.el5_11.1.x86_64.rpm \
glibc-devel-2.5-123.el5_11.1.x86_64.rpm \
glibc-headers-2.5-123.el5_11.1.x86_64.rpm \
nscd-2.5-123.el5_11.1.x86_64.rpm
* '''Note''': that operation might take a long time since yum will probably experience timeouts when trying to access the external repositories.
* Reboot the unit
reboot

= How to verify if the vulnerability is fixed? =
* login with root account
* execute the following to create a test script
cat >> rhel-GHOST-test.sh << FOF
#!/bin/bash
# rhel-GHOST-test.sh - GHOST vulnerability tester. Only for CentOS/RHEL based servers. #
# Version 3
# Credit : Red Hat, Inc - https://access.redhat.com/labs/ghost/ #
echo "Installed glibc version(s)"

rv=0
for glibc_nvr in $( rpm -q --qf '%{name}-%{version}-%{release}.%{arch}\n' glibc ); do
glibc_ver=$( echo "$glibc_nvr" | awk -F- '{ print $2 }' )
glibc_maj=$( echo "$glibc_ver" | awk -F. '{ print $1 }')
glibc_min=$( echo "$glibc_ver" | awk -F. '{ print $2 }')

echo -n "- $glibc_nvr: "
if [ "$glibc_maj" -gt 2 -o \
$ "$glibc_maj" -eq 2 -a "$glibc_min" -ge 18 $ ]; then
# fixed upstream version
echo 'not vulnerable'
else
# all RHEL updates include CVE in rpm %changelog
if rpm -q --changelog "$glibc_nvr" | grep -q 'CVE-2015-0235'; then
echo "not vulnerable"
else
echo "vulnerable"
rv=1
fi
fi
done

if [ $rv -ne 0 ]; then
cat <<EOF

This system is vulnerable to CVE-2015-0235. <https://access.redhat.com/security/cve/CVE-2015-0235>
Please refer to <https://access.redhat.com/articles/1332213> for remediation steps
EOF
fi

exit $rv
FOF
* Execute the script
chmod +x rhel-GHOST-test.sh
./rhel-GHOST-test.sh
* '''You should not see the 'vulnerable' string displayed'''

= References =
* https://www.qualys.com/research/security-advisories/GHOST-CVE-2015-0235.txt
* https://access.redhat.com/articles/1332213
* http://www.cyberciti.biz/faq/cve-2015-0235-patch-ghost-on-debian-ubuntu-fedora-centos-rhel-linux/

@@ Line 17: / Line 17: @@
 == WebPortal - TMG unit or Linux server '''with access to Internet''' (i.e. with DNS configured) ==
-* login onto the WebPortal
+# login onto the WebPortal
-* Select the 'Hosts' section
+# Select the 'Hosts' section
-* Click on the hostname
+# Click on the hostname
-* Click on the 'Status' tab
+# Click on the 'Status' tab
-* Select 'Upgrade Linux packages' into the host 'Action'
+# Select 'Upgrade Linux packages' into the host 'Action'
-* Click on the 'Apply action' button
+# Click on the 'Apply action' button
-* Refresh the page until the packages are updated as indicated in the 'Action Log' (you may use the 'Now' button to update the page). The results should appear within a minute.
+# Refresh the page until the packages are updated as indicated in the 'Action Log' (you may use the 'Now' button to update the page). The results should appear within a minute.
-* Select 'Shutdown' into the host 'Action'
+# Select 'Shutdown' into the host 'Action'
-* Select 'Reboot' into the 'Shutdown Type'
+# Select 'Reboot' into the 'Shutdown Type'
-* Click on the 'Apply action' button
+# Click on the 'Apply action' button
-* Repeat the process for all hosts listed
+# Repeat the process for all hosts listed
 == Command line interface ==

@@ Line 23: / Line 23: @@
 * Select 'Upgrade Linux packages' into the host 'Action'
 * Click on the 'Apply action' button
 * Select 'Shutdown' into the host 'Action'
 * Select 'Reboot' into the 'Shutdown Type'

@@ Line 17: / Line 17: @@
 == WebPortal - TMG unit or Linux server '''with access to Internet''' (i.e. with DNS configured) ==
-# login onto the WebPortal
+* login onto the WebPortal
-# Select the 'Hosts' section
+* Select the 'Hosts' section
-# Click on the hostname
+* Click on the hostname
-# Click on the 'Status' tab
+* Click on the 'Status' tab
-# Select 'Upgrade Linux packages' into the host 'Control Action'
+* Select 'Upgrade Linux packages' into the host 'Action'
-# Click on the 'Apply action' button
+* Click on the 'Apply action' button
-# Repeat the process for all hosts listed
+* Select 'Shutdown' into the host 'Action'
 == Command line interface ==

@@ Line 110: / Line 110: @@
   ./rhel-GHOST-test.sh
 * '''You should not see the 'vulnerable' string displayed'''
 = References =

@@ Line 14: / Line 14: @@
 = Update procedure =
 * login with root account
   [root@TB011107 ~]# uname -m
   x86_64
 * If the result is not "x86_64", [[Support:Contacting TelcoBridges technical support|please contact TelcoBridges]] support, otherwise you can proceed with either method below.
 * update OS packages with yum
   yum clean all
@@ Line 27: / Line 41: @@
   reboot
-== TMG unit or Linux server '''without access to Internet''' ==
+=== Option #2 - TMG unit or Linux server '''without access to Internet''' ===
 * download the following packages to your PC:
 ** http://repo.telcobridges.com/centos/5.7/updates/x86_64/RPMS/glibc-2.5-123.el5_11.1.x86_64.rpm

@@ Line 49: / Line 49: @@
 * login with root account
 * execute the following to create a test script
-  cat >> rhel-GHOST-test.sh << FOF
+  cat > rhel-GHOST-test.sh << FOF
   #!/bin/bash
   # rhel-GHOST-test.sh -  GHOST vulnerability tester. Only for CentOS/RHEL based servers.  #
@@ Line 57: / Line 57: @@
   rv=0
-  for glibc_nvr in $( rpm -q --qf '%{name}-%{version}-%{release}.%{arch}\n' glibc ); do
+  for glibc_nvr in \$( rpm -q --qf '%{name}-%{version}-%{release}.%{arch}\n' glibc ); do
-      glibc_ver=$( echo "$glibc_nvr" | awk -F- '{ print $2 }' )
+      glibc_ver=\$( echo "\$glibc_nvr" | awk -F- '{ print \$2 }' )
-      glibc_maj=$( echo "$glibc_ver" | awk -F. '{ print $1 }')
+      glibc_maj=\$( echo "\$glibc_ver" | awk -F. '{ print \$1 }')
-      glibc_min=$( echo "$glibc_ver" | awk -F. '{ print $2 }')
+      glibc_min=\$( echo "\$glibc_ver" | awk -F. '{ print \$2 }')
-      echo -n "- $glibc_nvr: "
+      echo -n "- \$glibc_nvr: "
-      if [ "$glibc_maj" -gt 2   -o  \
+      if [ "\$glibc_maj" -gt 2 -o \( "\$glibc_maj" -eq 2  -a  "\$glibc_min" -ge 18 \) ]; then
-         \( "$glibc_maj" -eq 2  -a  "$glibc_min" -ge 18 \) ]; then
           # fixed upstream version
           echo 'not vulnerable'
       else
           # all RHEL updates include CVE in rpm %changelog
-          if rpm -q --changelog "$glibc_nvr" | grep -q 'CVE-2015-0235'; then
+          if rpm -q --changelog "\$glibc_nvr" | grep -q 'CVE-2015-0235'; then
               echo "not vulnerable"
           else
@@ Line 78: / Line 77: @@
   done
-  if [ $rv -ne 0 ]; then
+  if [ \$rv -ne 0 ]; then
       cat <<EOF
-  This system is vulnerable to CVE-2015-0235. <https://access.redhat.com/security/cve/CVE-2015-0235>
+ This system is vulnerable to CVE-2015-0235. <https://access.redhat.com/security/cve/CVE-2015-0235>
-  Please refer to <https://access.redhat.com/articles/1332213> for remediation steps
+ Please refer to <https://access.redhat.com/articles/1332213> for remediation steps
-  EOF
+ EOF
   fi
-  exit $rv
+  exit \$rv
   FOF
 * Execute the script