Four out of the five vendors shown last month by testing company NSS Labs to suffer a security flaw in their high-end firewalls have since patched their products, including two companies that disputed the issue at the time.
A statement released by NSS Labs confirmed that Fortinet, SonicWALL and Palo Alto Networks had now updated their products to fix the TCP split handshake issue revealed on 12 April, while Juniper Networks had addressed it by altering the product's default setting.
One company, Cisco, has yet to issue a patch but recommended a workaround using access control lists that avoided the issue in some but not all cases.
In the days after publication, the NSS Labs tests proved controversial, with one company, Fortinet, which disputed the significance of the flaw. The vendor claimed that the issue could be prevented by turning on the company's separate intrusion prevention system (IPS) and antivirus security modules.
"NSS Labs incorrectly states that Fortinet does not currently provide customers with protection against a TCP split handshake," said Fortinet's VP of product marketing, Patrick Bedwell, at the time.
"We feel strongly that integrated protection is the best approach for blocking this issue, as customers that have IPS working with their firewall are better protected against a wider range of threats," said Bedwell.
The tests also upset SonicWALL. "This claim [the TCP split handshake attack vulnerability] is not correct since SonicOS has had the referenced TCP Split Handshake Spoof protection since SonicOS 3.0 released in 2004. Regrettably, NSS chose not to enable it for their testing despite our insistence on it being enabled for proper results," said company PR Director Jock Breitwieser.
Although neither company denied the likelihood of a patch being necessary, that they have been issued rapidly suggests a calmer assessment of the NSS tests now that the heat of the moment has passed.
"Only this kind of rigorous, unsponsored testing could have uncovered these types of critical issues. Product quality is a big issue in the security industry," said NSS Labs head Rick Moy. "That most vendors are ultimately fixing the problem validates our work, despite a vendor's initial marketing response."
The affair could yet turn out to be a significant moment for the security appliance industry. There has been criticism in the past that vendors have over-relied on product testing that was not independent enough to reveal important security issues to the businesses that buy the products. The NSS Labs firewall tests were sponsored by unnamed financial services companies and not vendors.
The five firewalls affected by the TCP split handshake flaw were the Fortinet Fortigate 3950 series, SonicWall NSA E8500, Palo Alto Networks PA-4020, Juniper SRX5800 and Cisco ASA 5585-40. Only one product looked at, Check Point's Power-1 11065, did not suffer from the flaw. Patching advice can be found through each vendor's Web support system, although NSS Labs has advised companies to test the patches carefully first.
"Enabling this protection may have a negative impact on performance and/or break applications that are not using TCP properly," said NSS Labs in its statement.