BSD systems could allow attackers to reset arbitrary TCP connections
| bsd-rst-dos (3377) |  Medium Risk |
Description:
BSD is vulnerable to a denial of service attack that could allow a remote attacker with limited knowledge to reset arbitrary TCP connections. TCP RST packets are used to terminate old connections that were not torn down during normal operation of the stream. A flaw in the way some systems interpret the sequence numbers in RST packets used for "authentication" could allow arbitrary connections to be terminated by a third party.
Platforms Affected:
- FreeBSD, FreeBSD 2.2
- FreeBSD, FreeBSD 2.2.1
- FreeBSD, FreeBSD 2.2.2
- FreeBSD, FreeBSD 2.2.3
- FreeBSD, FreeBSD 2.2.4
- FreeBSD, FreeBSD 2.2.5
- FreeBSD, FreeBSD 2.2.6
- FreeBSD, FreeBSD 2.2.7
- FreeBSD, FreeBSD 2.2.8
- OpenBSD, OpenBSD 2.0
- OpenBSD, OpenBSD 2.1
- OpenBSD, OpenBSD 2.2
- OpenBSD, OpenBSD 2.3
- OpenBSD, OpenBSD 2.4
Remedy:
This hole was fixed in OpenBSD 2.5 and FreeBSD 2.2.8 and 3.x. Users who wish to fix this hole but not upgrade their systems should review the security advisory from their vendor and apply the patch information. See References.
Consequences:
Denial of Service
References:
- FreeBSD Security Advisory FreeBSD-SA-98:07, TCP RST denial of sevice at ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/old/FreeBSD-SA-98:07.rst.asc.
- OpenBSD Security Advisory, February 11, 1999, TCP/IP RST handling was too sloppy at http://www.openbsd.org/errata24.html#rst.
- CVE-1999-0053: TCP RST denial of service in FreeBSD.
- OSVDB ID: 6094: Multiple BSD TCP RST DoS
Reported:
Oct 13, 1998
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