Vulnerability Assessment & Network Security Forums
If through a vulnerability assessment, a network security issue is detected for the vulnerability below, applying the appropriate security patches in a timely matter is very important. If you have detected that your system has already been compromised, following CERT's Network Security recovery document will assist with recommended steps for system recovery.
Vulnerability Assessment Details
Linux Kernel: Remote DoS vulnerability with IPTables TCP Handling
Detailed Explanation for this Vulnerability Assessment
The remote host is affected by the vulnerability described in GLSA-200407-12
(Linux Kernel: Remote DoS vulnerability with IPTables TCP Handling)
A possible hacker can utilize an erroneous data type in the IPTables TCP option
handling code, which lies in an iterator. By making a TCP packet with a
header length larger than 127 bytes, a negative integer would be implied in
By sending one malformed packet, the kernel could get stuck in a loop,
consuming all of the CPU resources and rendering the machine useless,
causing a Denial of Service. This vulnerability requires no local access.
If users do not use the netfilter functionality or do not use any
``--tcp-option'' rules they are not vulnerable to this exploit. Users that
are may remove netfilter support from their kernel or may remove any
``--tcp-option'' rules they might be using. However, all users are urged to
upgrade their kernels to patched versions.
Users are encouraged to upgrade to the latest available sources for their
# emerge sync
# emerge -pv your-favorite-sources
# emerge your-favorite-sources
# # Follow usual procedure for compiling and installing a kernel.
# # If you use genkernel, run genkernel as you would do normally.
Network Security Threat Level: High
Networks Security ID:
Vulnerability Assessment Copyright: (C) 2005 Michel Arboi
|Cisco Catalyst 2960 WS-C2960G-8TC-L 8-Ports Gigabit 10/100/1000 Switch
|Brocade Silkworm 5000 / 16 Port 4 Gbit/s FC Switch
|Clavister Eagle E7 Firewall Rev. B Micro USB RJ45 11 Port 1000Base-T
|DELL PowerConnect 7048P 48 PT Gigabit PoE 4 PT SFP Layer 3 Switch
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