.

TCP split handshake vulernability in the most commonly-used firewalls.

<<

R3B005t

Newbie
Newbie

Posts: 43

Joined: Wed Mar 09, 2011 9:03 am

Location: NVA/D.C.

Post Tue Apr 19, 2011 1:13 pm

TCP split handshake vulernability in the most commonly-used firewalls.

What do you guys think?
New News? Old News? No News?

http://www.networkworld.com/news/2011/0 ... =pulsenews


Hacker 'handshake' hole found in common firewalls
NSS Labs tested Cisco, Check Point, Fortinet, Juniper, the Palo Alto Networks, and SonicWall firewalls
By Ellen Messmer, Network World
April 12, 2011 03:33 PM ET

Some of the most commonly-used firewalls are subject to a hacker exploit that lets an attacker trick a firewall and get into an internal network as a trusted IP connection.

More on security: 20 hot IT security issues

NSS Labs recently tested half a dozen network firewalls to evaluate security weaknesses, and all but one of them was found to be vulnerable to a type of attack called the "TCP Split Handshake Attack" that lets a hacker remotely fool the firewall into thinking an IP connection is a trusted one behind the firewall.

To continue reading, register here to become an Insider. You'll get free access to premium content from CIO, Computerworld, CSO, InfoWorld, and Network World. See more Insider content or sign in.

Some of the most commonly-used firewalls are subject to a hacker exploit that lets an attacker trick a firewall and get into an internal network as a trusted IP connection.

NSS Labs recently tested half a dozen network firewalls to evaluate security weaknesses, and all but one of them was found to be vulnerable to a type of attack called the "TCP Split Handshake Attack" that lets a hacker remotely fool the firewall into thinking an IP connection is a trusted one behind the firewall.

"If the firewall thinks you're inside, the security policy it applies to you is an internal one, and you can run a scan to see where machines are," says Rick Moy, president of NSS Labs. An attacker can then pretty much run wild in the network because the firewall mistakenly considers the IP address as a trusted one coming from behind the firewall.

This week NSS Labs published its "Network Firewall 2011 Comparative Test Results" research paper about the findings. NSS Labs is a well-known product testing organization that evaluates a wide range of security gear, sometimes as vendor-sponsored comparative tests, sometimes as completely independent tests under its own determination. The Network Firewall 2011 Comparative Test published this week is in the latter category, where costs were assumed wholly by NSS Labs itself.

NSS Labs independently tested the Check Point Power-1 11065, the Cisco ASA 5585-40, the Fortinet Fortigate 3950, the Juniper SRX 5800, the Palo Alto Networks PA-4020, and the SonicWall NSA E8500.

Moy pointed out that vendors were generally reluctant to participate in the battery of tests that NSS Labs did and that in fact about half the firewall equipment in the tests was contributed directly by end-user customers, such as financial services firms, which supported the tests because they wanted to find out about possible vulnerabilities in their firewalls.

The NSS Labs report says, "Five of the six products allowed external attackers to bypass the firewall and become an internal 'trusted machine.'" The only firewall tested by NSS labs that didn't was the Check Point one.

Moy says the exploit used in the test is known as the "TCP Split Handshake," which begins during the point that the firewall and any connection is being initiated during the TCP "handshake" process to set up a connection. Moy says attack code in the wild has been known for about a year. It's '"an easy way for an attacker to become part of the network," he says. What's particularly insidious about it is that since it occurs at the handshake stage, they are unlikely to be logs and alerts associated with the attack, Moy says.

The vendors whose equipment did not pass the "TCP Split Handshake" security test are in varying stages of remediation, according to the report.

Cisco is said to be currently working with NSS Labs on this issue and "recommendations will be provided as soon as they are available."

"Fortinet does not currently provide their customers protection against the TCP Split handshake attack," the report says, but NSS Labs says Fortinet has advised the lab that one will be included in an upcoming release in May.
<<

mallaigh

User avatar

Jr. Member
Jr. Member

Posts: 65

Joined: Fri Jul 16, 2010 12:36 am

Post Tue Apr 19, 2011 3:16 pm

Re: TCP split handshake vulernability in the most commonly-used firewalls.

Pretty interesting R3B005t, thanks for sharing.  On the second page of the article (looks like you got cut off), Juniper and Sonicwall have options which are disabled by default, but protect against this. 

I think the article is a little bit of FUD mixed with a side of mis-configurations.  But, I wouldn't be surprised to hear some of the other admins in my office say: "See, I told you companyA and companyB suck!".  Where I don't really feel it should turn into finger pointing, but an nudge to go through those firewall configs and a thorough check for possible breaches if your firewall is vulnerable/mis-configured. 
<<

hell_razor

User avatar

Jr. Member
Jr. Member

Posts: 90

Joined: Wed Jul 14, 2010 10:44 am

Post Tue Apr 19, 2011 3:39 pm

Re: TCP split handshake vulernability in the most commonly-used firewalls.

Fortinet does in fact provide the protection, but at the time of the writing of the article, it was defaulted to disabled in the IPS settings.  Not their fault, a security person should know what is enabled and disabled.  I believe they are publishing (or may already have) an update to make it enabled in the IPS, but IPS is not forced on any time.  It still has to be turned on, as it should be IMHO.
A+, Network+, Server+, CISSP, GSEC, GCIH, GPEN, GCIA, GISP, GCFW
<<

R3B005t

Newbie
Newbie

Posts: 43

Joined: Wed Mar 09, 2011 9:03 am

Location: NVA/D.C.

Post Wed Apr 20, 2011 5:43 am

Re: TCP split handshake vulernability in the most commonly-used firewalls.

mallaigh wrote:Pretty interesting R3B005t, thanks for sharing.  On the second page of the article (looks like you got cut off), Juniper and Sonicwall have options which are disabled by default, but protect against this. 

I think the article is a little bit of FUD mixed with a side of mis-configurations.  But, I wouldn't be surprised to hear some of the other admins in my office say: "See, I told you companyA and companyB suck!".  Where I don't really feel it should turn into finger pointing, but an nudge to go through those firewall configs and a thorough check for possible breaches if your firewall is vulnerable/mis-configured. 


That's what really got me, it appears that they are basing the studies off of fresh out of the box default configurations instead of something hardened and "production" ready.  I haven't started digging though the hardening standards to see if those options are listed as recommended.
<<

SephStorm

User avatar

Hero Member
Hero Member

Posts: 569

Joined: Sat Apr 17, 2010 12:12 pm

Post Wed Apr 20, 2011 7:53 am

Re: TCP split handshake vulernability in the most commonly-used firewalls.

looks like these are all hardware based solutions. should we assume software based solutions are vulnerable as well? I found a linux based test, but no test for a windows based system.
sectestanalysis.blogspot.com/‎
<<

karim.hamandi

Newbie
Newbie

Posts: 1

Joined: Fri Apr 22, 2011 12:34 am

Post Fri Apr 22, 2011 12:41 am

Re: TCP split handshake vulernability in the most commonly-used firewalls.

Actually NSS labs, in their report brief, report a wrong cisco psirt bug ID. the bug id is for IOS based firewalls. the bug has been closed by cisco because they were not able to replicate the vulnerability. meaning, IOS firewall was not vulnerable and was able to block split handshake. the same goes for ASA based firewalls.
as for fortinet, yes they are not vulnerable IF you enable antivirus and IPS services. The NSS labs test was for Firewall vendors, not for IPS vendors. as you all know, enabling IPS services incurs extra cost, and a noticeable degradation to performance.

Return to Malware

Who is online

Users browsing this forum: No registered users and 0 guests

.
Powered by phpBB® Forum Software © phpBB Group.
Designed by ST Software