SYMSA1012

Symantec Norton Personal Firewall 2002 SYN/FIN scan issue

Last Updated May 16, 2002
Initial Publication Date May 16, 2002
  • Status: Closed
  • Severity: Low
  • CVSS Base Score:

Symantec is aware of two issues with the Symantec Norton Personal Firewall 2002. A Microsoft Windows 2000 system is exposed during a SYN/FIN scan with Symantec Norton Personal Firewall 2002 installed. Additionally, a Jolt2 IP fragmentation attack will succeed against a non-patched Microsoft Windows 2000 computer running Symantec Norton Personal Firewall 2002.

Components Affected
Norton Personal Firewall 2002
Norton Internet Security 2002

Description
On 16 April, 2002, Symantec became aware of a SYN/FIN scan issue reported on SecurityFocus. By using a SYN/FIN scan, an attacker would be able to port scan a Microsoft Windows 2000 computer so that the computer responds even if Symantec Norton Personal Firewall 2002 is installed. A second reported issue states that a plain install of a Microsoft Windows 2000 system with Symantec Norton Personal Firewall 2002 installed is susceptible to a packet fragmentation denial of service (DoS) attack known as Jolt2.

Symantec Response
Symantec has evaluated both issues. Although a Microsoft Windows 2000 computer can be detected through the SYN/FIN scan, Symantec Norton Personal Firewall 2002 continues to protect the computer from an actual intrusion by blocking connections to the computer.

Because Symantec takes the security of its customers very seriously, an update to Symantec Norton Personal Firewall 2002 and Symantec Norton Internet Security 2002 has been made available via Symantec's LiveUpdate to address this concern. Users of Symantec Norton Personal Firewalls running the latest updates are fully protected.

To protect users from Jolt2 DoS attacks against Microsoft Windows 2000 computers, Symantec recommends that Microsoft Windows 2000 Service Pack 1 (SP1) or later be installed. Microsoft Windows 2000 with SP1 or later is not susceptible to this problem. The latest updates for Microsoft products can be obtained from the Microsoft Windows Update site.

As a best practice, Symantec recommends keeping all operating systems and applications updated with the latest vendor patches. Keeping mission-critical systems updated with all security patches applied reduces risk exposure.

Symantec further recommends using a multi-layered approach to security. Users, at a minimum, should run both personal firewall and antivirus applications to provide multiple points of detection and protection to both inbound and outbound threats.

SYM02-008

Thanks for your feedback. Let us know if you have additional comments below. (requires login)