Title: Multiple Vendor Small TCP MSS Denial of Service Vulnerability
Severity: HIGH
Description:
A potential denial of service vulnerability exists in several TCP stack implementations.
TCP has a MSS (maximum segment size) option that is used by a TCP client to announce to a peer the maximum amount of TCP data that can be sent per segment. The MSS is sent during connection establishment, and is often set to the interface MTU minus the fixed sizes of the IP and TCP headers. This is usually 1460 on an Ethernet using IPv4, or 1440 on an Ethernet using IPv6.
When data of a length exceeding the MSS is written to a TCP socket, it is broken down into segments before being passed to IP. For example, if an application writes 2048 bytes of data to a TCP socket with the MSS set to 256, a total of 8 segments are transmitted. Using IPv4, this incurs an additional 320 bytes for IP and TCP header data. Using IPv6, the amount increases to 480 bytes. Sending a large number of packets often also means a significant increase in the workload of the system sending the data.
The potential for attacks against TCP stack implementations exists because in many cases only a small minimum value is enforced for the MSS. By setting the MSS to a low value (such as 1) and making requests for large amounts of data through a TCP service, an attacker could effectively cause a denial of service by causing a large workload on a system.
Affected Products:
- Avaya DefinityOne Media Servers
- Avaya IP600 Media Servers
- Avaya S3400 Message Application Server
- Avaya S8100 Media Servers
- Caldera OpenLinux Server 3.1.0
- Caldera OpenLinux Workstation 3.1.0
- FreeBSD FreeBSD 4.3.0
- HP HP-UX (VVOS) 11.0.4
- HP HP-UX 11.0.0
- HP HP-UX 11.0.0 4
- HP HP-UX 11.11.0
- Linux kernel 2.4.0
- Linux kernel 2.4.1
- Linux kernel 2.4.2
- Linux kernel 2.4.3
- Linux kernel 2.4.4
- Linux kernel 2.4.5
- MandrakeSoft Linux Mandrake 8.0.0
- MandrakeSoft Linux Mandrake 8.0.0 ppc
- Microsoft Windows 2000 Advanced Server
- Microsoft Windows 2000 Advanced Server SP1
- Microsoft Windows 2000 Advanced Server SP2
- Microsoft Windows 2000 Datacenter Server
- Microsoft Windows 2000 Datacenter Server SP1
- Microsoft Windows 2000 Datacenter Server SP2
- Microsoft Windows 2000 Professional
- Microsoft Windows 2000 Professional SP1
- Microsoft Windows 2000 Professional SP2
- Microsoft Windows 2000 Server
- Microsoft Windows 2000 Server SP1
- Microsoft Windows 2000 Server SP2
- Microsoft Windows 2000 Terminal Services
- Microsoft Windows 2000 Terminal Services SP1
- Microsoft Windows 2000 Terminal Services SP2
- Microsoft Windows NT 4.0
- Microsoft Windows NT 4.0 SP1
- Microsoft Windows NT 4.0 SP2
- Microsoft Windows NT 4.0 SP3
- Microsoft Windows NT 4.0 SP4
- Microsoft Windows NT 4.0 SP5
- Microsoft Windows NT 4.0 SP6
- Microsoft Windows NT 4.0 SP6a
- Microsoft Windows NT Enterprise Server 4.0
- Microsoft Windows NT Enterprise Server 4.0 SP1
- Microsoft Windows NT Enterprise Server 4.0 SP2
- Microsoft Windows NT Enterprise Server 4.0 SP3
- Microsoft Windows NT Enterprise Server 4.0 SP4
- Microsoft Windows NT Enterprise Server 4.0 SP5
- Microsoft Windows NT Enterprise Server 4.0 SP6
- Microsoft Windows NT Enterprise Server 4.0 SP6a
- Microsoft Windows NT Server 4.0
- Microsoft Windows NT Server 4.0 SP1
- Microsoft Windows NT Server 4.0 SP2
- Microsoft Windows NT Server 4.0 SP3
- Microsoft Windows NT Server 4.0 SP4
- Microsoft Windows NT Server 4.0 SP5
- Microsoft Windows NT Server 4.0 SP6
- Microsoft Windows NT Server 4.0 SP6a
- Microsoft Windows NT Terminal Server 4.0
- Microsoft Windows NT Terminal Server 4.0 SP1
- Microsoft Windows NT Terminal Server 4.0 SP2
- Microsoft Windows NT Terminal Server 4.0 SP3
- Microsoft Windows NT Terminal Server 4.0 SP4
- Microsoft Windows NT Terminal Server 4.0 SP5
- Microsoft Windows NT Terminal Server 4.0 SP6
- Microsoft Windows NT Terminal Server 4.0 SP6a
- Microsoft Windows NT Workstation 4.0
- Microsoft Windows NT Workstation 4.0 SP1
- Microsoft Windows NT Workstation 4.0 SP2
- Microsoft Windows NT Workstation 4.0 SP3
- Microsoft Windows NT Workstation 4.0 SP4
- Microsoft Windows NT Workstation 4.0 SP5
- Microsoft Windows NT Workstation 4.0 SP6
- Microsoft Windows NT Workstation 4.0 SP6a
- NetBSD NetBSD 1.5.0
- NetBSD NetBSD 1.5.1
- OpenBSD OpenBSD 2.8.0
- OpenBSD OpenBSD 2.9.0
- RedHat Linux 7.1.0 alpha
- RedHat Linux 7.1.0 i386
- S.u.S.E. Linux 7.2.0
- SGI IRIX 6.5.0
- SGI IRIX 6.5.1
- SGI IRIX 6.5.10
- SGI IRIX 6.5.11
- SGI IRIX 6.5.12
- SGI IRIX 6.5.13
- SGI IRIX 6.5.14 f
- SGI IRIX 6.5.14 m
- SGI IRIX 6.5.15 f
- SGI IRIX 6.5.15 m
- SGI IRIX 6.5.16 f
- SGI IRIX 6.5.16 m
- SGI IRIX 6.5.17 f
- SGI IRIX 6.5.17 m
- SGI IRIX 6.5.18 f
- SGI IRIX 6.5.18 m
- SGI IRIX 6.5.2
- SGI IRIX 6.5.3
- SGI IRIX 6.5.4
- SGI IRIX 6.5.5
- SGI IRIX 6.5.6
- SGI IRIX 6.5.7
- SGI IRIX 6.5.8
- SGI IRIX 6.5.9
- Slackware Linux 8.0.0
- Sun Solaris 2.5.1
- Sun Solaris 7.0
- Sun Solaris 8
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