Patrick,

Thanks for clarifying.  Turns out I did the config right from the get-go, just 
got momentarily confused by all of the port numbers. :)

===

For anyone who’s running CentOS/RHEL boxes, here’s what we used for a 3-node 
ZooKeeper cluster with static IPs, to limit access to the election & quorum 
ports only to the cluster members (if using 2888 & 3888) .

# Open the firewall for Zookeeper
sudo firewall-cmd --zone=public --add-port=2181/tcp --permanent

# Open up the ZooKeeper cluster & election ports to each other
IP1=`dig +short $ZOOKEEPER_SERVER1`
IP2=`dig +short $ZOOKEEPER_SERVER2`
IP3=`dig +short $ZOOKEEPER_SERVER3`
sudo firewall-cmd --permanent --zone=public --add-rich-rule="
  rule family=\"ipv4\"
  source address=\"$IP1/32\"
  port protocol=\"tcp\" port=\"2888\" accept"
sudo firewall-cmd --permanent --zone=public --add-rich-rule="
  rule family=\"ipv4\"
  source address=\"$IP1/32\"
  port protocol=\"tcp\" port=\"3888\" accept"
sudo firewall-cmd --permanent --zone=public --add-rich-rule="
  rule family=\"ipv4\"
  source address=\"$IP2/32\"
  port protocol=\"tcp\" port=\"2888\" accept"
sudo firewall-cmd --permanent --zone=public --add-rich-rule="
  rule family=\"ipv4\"
  source address=\"$IP2/32\"
  port protocol=\"tcp\" port=\"3888\" accept"
sudo firewall-cmd --permanent --zone=public --add-rich-rule="
  rule family=\"ipv4\"
  source address=\"$IP3/32\"
  port protocol=\"tcp\" port=\"2888\" accept"
sudo firewall-cmd --permanent --zone=public --add-rich-rule="
  rule family=\"ipv4\"
  source address=\"$IP3/32\"
  port protocol=\"tcp\" port=\"3888\" accept"

# Restart the firewall so the changes take effect
sudo firewall-cmd --reload


[cid:[email protected]]

Philip Lowman
Sr. Software Security Engineer



WorkForce Software |  38705 Seven Mile Road, Livonia, MI 48152
T: +1 734-742-3610 |  E: 
[email protected]<mailto:[email protected]>





On May 26, 2018, at 2:45 PM, Patrick Hunt 
<[email protected]<mailto:[email protected]>> wrote:



On Fri, May 25, 2018 at 8:38 AM Philip Lowman 
<[email protected]<mailto:[email protected]>> wrote:
Hello,

In regards to the 
CVE-2018-8012<https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.apache.org%2Fthread.html%2Fc75147028c1c79bdebd4f8fa5db2b77da85de2b05ecc0d54d708b393%40%253Cdev.zookeeper.apache.org%253E&data=02%7C01%7C%7Ce1c7476001cb487bd36008d5c338e402%7Cc61157e903cb47589165ee7845cb0ca3%7C0%7C0%7C636629571472840072&sdata=%2Fu02%2FxaVgav%2FkTV%2FIimBspc6vQkTiOjNAwmPJCrtq%2FM%3D&reserved=0>
 advisory posted on Monday, it contains the following statement “Alternatively 
ensure the ensemble election/quorum communication is protected by a firewall as 
this will mitigate the issue”.

I just wanted to ask (or hopefully just confirm), does this communication 
exclusively travel over the “leader election port”?

In example configuration files the leader election port (see server.x in the 
docs<https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fzookeeper.apache.org%2Fdoc%2Fcurrent%2FzookeeperAdmin.html%23sc_configuration&data=02%7C01%7C%7Ce1c7476001cb487bd36008d5c338e402%7Cc61157e903cb47589165ee7845cb0ca3%7C0%7C0%7C636629571472996325&sdata=3EqVaR3%2FFh%2B4SNOWH9l3xHlH9KZLU6Th3fpcTztMNVs%3D&reserved=0>)
 is typically defined to be port 3888.

server.1=zoo1:2888:3888
server.2=zoo2:2888:3888
server.3=zoo3:2888:3888

Hi Philip,

The firewall would need to protect both the election and quorum ports - those 
are the two numbers at the end of the server.# configuration parameters. See
http://zookeeper.apache.org/doc/current/zookeeperAdmin.html#sc_clusterOptions<https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fzookeeper.apache.org%2Fdoc%2Fcurrent%2FzookeeperAdmin.html%23sc_clusterOptions&data=02%7C01%7C%7Ce1c7476001cb487bd36008d5c338e402%7Cc61157e903cb47589165ee7845cb0ca3%7C0%7C0%7C636629571472996325&sdata=nKQJ1pUhOorUkz5d7wbo1afLv8ipHG7MEyl%2B02nWC7E%3D&reserved=0>
for more details on that config option.

Patrick


Thanks


[cid:[email protected]]

Philip Lowman
Sr. Software Security Engineer



WorkForce Software |  38705 Seven Mile Road, Livonia, MI 48152
T: +1 734-742-3610 |  E: 
[email protected]<mailto:[email protected]>








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