Title: Linux Syn Filter Evasion Vulnerability
Severity: HIGH
Description:
The packet filtering engine included in the Linux kernel contains a feature called 'syn cookies'. Syn cookies are a cryptographic challenge-response system that can be used to protect against some syn flood attacks.
Before allocating a socket to a host requesting a TCP connection during a detected syn flood, a challenge called a 'cookie' must be answered. The idea behind syn cookies is that legitimate hosts will be able to answer the challenges, while the attacking host (possibly spoofed) will not.
There exists a vulnerability in the packet filter that may allow for attackers to evade certain rules if syn cookies are in use.
When processing connection requests in syn-flood protection mode, filter rules for TCP packets with the syn flag set (connection requests) are not properly enforced. If an attacker can guess a valid syn cookie response, it may be possible for them to access services otherwise filtered for all connection requests.
This may expose vulnerable services thought to be protected by filter rules to attackers.
Affected Products:
- Caldera OpenLinux 2.3.0
- Caldera OpenLinux 2.4.0
- Caldera OpenLinux Server 3.1.0
- Caldera OpenLinux Server 3.1.1
- Caldera OpenLinux Workstation 3.1.0
- Caldera OpenLinux Workstation 3.1.1
- Conectiva Linux 4.0.0
- Conectiva Linux 4.0.0 es
- Conectiva Linux 4.1.0
- Conectiva Linux 4.2.0
- Conectiva Linux 5.0.0
- Conectiva Linux 5.1.0
- Conectiva Linux 6.0.0
- Conectiva Linux 7.0.0
- Conectiva Linux ecommerce
- Conectiva Linux graficas
- Debian Linux 2.2.0
- Debian Linux 2.2.0 68k
- Debian Linux 2.2.0 alpha
- Debian Linux 2.2.0 arm
- Debian Linux 2.2.0 powerpc
- Debian Linux 2.2.0 sparc
- EnGarde Secure Linux 1.0.1
- Immunix Immunix OS 7+
- Linux kernel 2.0.0
- Linux kernel 2.0.1
- Linux kernel 2.0.10
- Linux kernel 2.0.11
- Linux kernel 2.0.12
- Linux kernel 2.0.13
- Linux kernel 2.0.14
- Linux kernel 2.0.15
- Linux kernel 2.0.16
- Linux kernel 2.0.17
- Linux kernel 2.0.18
- Linux kernel 2.0.19
- Linux kernel 2.0.2
- Linux kernel 2.0.20
- Linux kernel 2.0.21
- Linux kernel 2.0.22
- Linux kernel 2.0.23
- Linux kernel 2.0.24
- Linux kernel 2.0.25
- Linux kernel 2.0.26
- Linux kernel 2.0.27
- Linux kernel 2.0.28
- Linux kernel 2.0.29
- Linux kernel 2.0.3
- Linux kernel 2.0.30
- Linux kernel 2.0.31
- Linux kernel 2.0.32
- Linux kernel 2.0.33
- Linux kernel 2.0.34
- Linux kernel 2.0.35
- Linux kernel 2.0.36
- Linux kernel 2.0.37
- Linux kernel 2.0.38
- Linux kernel 2.0.39
- Linux kernel 2.0.4
- Linux kernel 2.0.5
- Linux kernel 2.0.6
- Linux kernel 2.0.7
- Linux kernel 2.0.8
- Linux kernel 2.0.9
- Linux kernel 2.2.0
- Linux kernel 2.2.1
- Linux kernel 2.2.10
- Linux kernel 2.2.11
- Linux kernel 2.2.12
- Linux kernel 2.2.13
- Linux kernel 2.2.14
- Linux kernel 2.2.15
- Linux kernel 2.2.16
- Linux kernel 2.2.17
- Linux kernel 2.2.18
- Linux kernel 2.2.19
- Linux kernel 2.2.2
- Linux kernel 2.2.20
- Linux kernel 2.2.3
- Linux kernel 2.2.4
- Linux kernel 2.2.5
- Linux kernel 2.2.6
- Linux kernel 2.2.7
- Linux kernel 2.2.8
- Linux kernel 2.2.9
- Linux kernel 2.4.0
- Linux kernel 2.4.1
- Linux kernel 2.4.10
- Linux kernel 2.4.11
- Linux kernel 2.4.12
- Linux kernel 2.4.13
- Linux kernel 2.4.2
- Linux kernel 2.4.3
- Linux kernel 2.4.4
- Linux kernel 2.4.5
- Linux kernel 2.4.6
- Linux kernel 2.4.7
- Linux kernel 2.4.8
- Linux kernel 2.4.9
- MandrakeSoft Corporate Server 1.0.1
- MandrakeSoft Linux Mandrake 6.0.0
- MandrakeSoft Linux Mandrake 6.1.0
- MandrakeSoft Linux Mandrake 7.0.0
- MandrakeSoft Linux Mandrake 7.1.0
- MandrakeSoft Linux Mandrake 7.2.0
- MandrakeSoft Linux Mandrake 8.0.0
- MandrakeSoft Linux Mandrake 8.0.0 ppc
- MandrakeSoft Linux Mandrake 8.1.0
- MandrakeSoft Linux Mandrake 8.2.0
- MandrakeSoft Linux Mandrake 8.2.0 ppc
- MandrakeSoft Single Network Firewall 7.2.0
- RedHat Enterprise Linux AS 2.1
- RedHat Enterprise Linux AS 2.1 IA64
- RedHat Enterprise Linux ES 2.1
- RedHat Enterprise Linux ES 2.1 IA64
- RedHat Enterprise Linux WS 2.1
- RedHat Enterprise Linux WS 2.1 IA64
- RedHat Linux 6.0.0
- RedHat Linux 6.0.0 alpha
- RedHat Linux 6.0.0 sparc
- RedHat Linux 6.1.0 alpha
- RedHat Linux 6.1.0 i386
- RedHat Linux 6.1.0 sparc
- RedHat Linux 6.2.0
- RedHat Linux 6.2.0 alpha
- RedHat Linux 6.2.0 i386
- RedHat Linux 6.2.0 sparc
- RedHat Linux 7.0.0
- RedHat Linux 7.0.0 alpha
- RedHat Linux 7.0.0 i386
- RedHat Linux 7.0.0 sparc
- RedHat Linux 7.1.0 alpha
- RedHat Linux 7.1.0 i386
- RedHat Linux 7.1.0 ia64
- RedHat Linux 7.2.0
- RedHat Linux 7.2.0 alpha
- RedHat Linux 7.2.0 i386
- RedHat Linux 7.2.0 ia64
- S.u.S.E. Linux 6.0.0
- S.u.S.E. Linux 6.1.0
- S.u.S.E. Linux 6.1.0 alpha
- S.u.S.E. Linux 6.3.0
- S.u.S.E. Linux 6.3.0 alpha
- S.u.S.E. Linux 6.3.0 ppc
- S.u.S.E. Linux 6.4.0
- S.u.S.E. Linux 6.4.0 alpha
- S.u.S.E. Linux 6.4.0 ppc
- S.u.S.E. Linux 7.0.0
- S.u.S.E. Linux 7.1.0
- S.u.S.E. Linux 7.2.0
- S.u.S.E. Linux 7.3.0
- SCO eDesktop 2.4.0
- SCO eServer 2.3.1
- Slackware Linux 4.0.0
- Slackware Linux 7.0.0
- Slackware Linux 7.1.0
- Slackware Linux 8.0.0
- Sun Cobalt Qube 3
- Sun Cobalt RaQ 4
- Sun Cobalt RaQ XTR
- Sun Linux 5.0.0
- Sun Linux 5.0.3
- Sun Linux 5.0.5
- Trustix Secure Linux 1.1.0
- Trustix Secure Linux 1.2.0
- Trustix Secure Linux 1.5.0
- WireX Immunix OS 6.2.0
- WireX Immunix OS 7.0.0
- WireX Immunix OS 7.0.0 -Beta
Juniper Networks provides this content via a wide variety of sources and production methods. If notified of errors or omissions in the content of this page, Juniper Networks, at its discretion, will modify or remove the page or leave the content as is, depending on various factors including but not limited to the reputation and authority of the party providing the notification. Please use the contact information displayed elsewhere on this page to report any errors or omissions regarding the content on this page.
