Kerio Personal Firewall Administration Port Lets Remote Users Deny Service
SecurityTracker Alert ID: 1013850|
SecurityTracker URL: http://securitytracker.com/id/1013850
(Links to External Site)
Date: Apr 30 2005
Denial of service via network|
Fix Available: Yes Vendor Confirmed: Yes |
Version(s): 4.1.2 and prior versions|
A vulnerability was reported in Kerio Personal Firewall. A remote user can cause denial of service conditions via the remote administration port.|
A remote user connect to the administration port (44334) and supply specially crafted data to cause denial of service conditions. A remote user can also exceed the maximum number of allowed simultaneous connections to cause denial of service conditions.
The attack is not logged.
Secure Computer Group and dotpi.com Information Technologies Research Labs reported this vulnerability. Javier Munoz (Secure Computer Group) discovered this vulnerability.
A remote user can cause denial of service conditions.|
The vendor has issued a fixed version (4.1.3), available at:|
Vendor URL: www.kerio.com/ (Links to External Site)
Exception handling error, State error|
|Underlying OS: Windows (Any)|
Source Message Contents
Subject: [CVE-2005-1063] Administration protocol abuse leads to Service and|
Secure Computer Group - University of A Coruna
-- x --
dotpi.com Information Technologies Research Labs
Document title: Administration protocol abuse leads to
Service and System Denial of Service
Document revision: 1.0
Coordinated release date: 2005/04/29
Vendor Acknowledge date: 2005/02/25
Reported date: 2005/02/21
CVE Name: CAN-2005-1063
Other references: N/A
Impact: Service denial of service (DoS)
CPU hogging denial of service (DoS)
Recommendation: Update to latest version
Enforce network ACLs
Vendor: Kerio Technologies Inc.
o Kerio WinRoute Firewall up to and including 6.0.10
o Kerio Personal Firewall up to and including 4.1.2
o Kerio MailServer up to and including 6.0.8
Updates/Patches: Yes (see below)
1. Executive summary:
Kerio WinRoute Firewall, Kerio Personal Firewall and Kerio
MailServer drive a local/remote administration protocol in order
to manage the service.
This protocol can be abused in pre-authentication states forcing
the service to compute unexpected conditions and also to perform
cryptographic operations over each protocol message.
As a result, system resources get exhausted and the system
becomes unresponsive. A sufficient network bandwidth between the
system and the attacker is required for the attack.
It must be noted that the limit of maximun number of user
connections can also be used to perform a service denial of
service and that no valid authentication is required for this to
The logging component of the software ignores any event related
with this attack.
In order solve this problem, system administrators should enforce
network ACL security settings. It is also highly recommended to
verify this settings as part of the planning, installation,
hardening and auditing processes.
New versions of the software solve this and other minor problems
so an upgrade is highly recommended.
2. Technical details:
Technical details and proof of concept code were provided to
3. Risk Assessment factors:
The attacker should have access to the administration ports:
o TCP/UDP 44333 - Kerio WinRoute Firewall Administration
o TCP/UDP 44334 - Kerio Personal Firewall Administration
o TCP/UDP 44337 - Kerio MailServer Administration
The most risky scenarios are the ones in which the server machine
is shared among two or more interactive users/administrators or
those situations where Kerio service management have been
delegated to a third party.
Special care should be taken on such environments and every step
of the project: design, planning, deployment and management
should consider this security issues.
4. Solutions and recommendations:
Upgrade to the latest versions:
o Kerio Winroute Firewall 6.0.11 and above
o Kerio Personal Firewall 4.1.3 and above
o Kerio MailServer 6.0.9 and above
As in any other case, follow, as much as possible, the Industry
'Best Practices' on Planning, Deployment and Operation on this
kind of services.
5. Common Vulnerabilities and Exposures (CVE) project:
The Common Vulnerabilities and Exposures (CVE) project has
assigned the name CAN-2005-1063 to this issue. This is a
candidate for inclusion in the CVE list (http://cve.mitre.org),
which standardizes names for security problems.
1. Special thanks to Vladimir Toncar and the whole Technical Team from
Kerio Technologies (support at kerio.com) for their quick response
and professional handling on this issue.
3. The whole Research Lab at dotpi.com and specially to Carlos Veira.
3. Secure Computer Group at University of A Coruna (scg at udc.es),
and specially to Antonino Santos del Riego.
Javier Munoz (Secure Computer Group) is credited with this discovery.
 Kerio Technologies Inc.
 Kerio WinRoute Firewall Downloads & Updates
 Kerio Personal Firewall Downloads & Updates
 Kerio MailServer Downloads & Updates
 Secure Computer Group. University of A Coruna
 Secure Computer Group. Updated advisory
 dotpi.com Information Technologies S.L.
 dotpi.com Research Labs
Copyright (c) 2002-2005 Secure Computer Group. University of A Coruna
Copyright (c) 2004-2005 dotpi.com Information Technologies S.L.
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