Signature Detail

DNS: Illegal Characters (UDP)

This signature detects the presence of invalid characters in a Domain Name System (DNS) request, which do not agree with the resource record defined in RFC1123. A successful attack could result in the execution of arbitrary code with higher privileges.

Extended Description

There are several vulnerabilities in recent BIND packages (pre 8.2.2). The first is a buffer overflow condition which is a result of BIND improperly validating NXT records. The consequence of this being exploited is a remote root compromise (assuming that BIND is running as root, which is default). The second is a denial of service which can occur if BIND does not validate SIG records properly. The next is a bug which allows attackers to cause BIND to consume more file descriptors than can be managed, causing named to crash. The fourth vulnerability is another denial of service which can be caused locally if certain permission conditions are met when validating zone information loaded from disk files. The last is a vulnerability which has to do with closing TCP sockets. If protocols for doing so are not adhered to, BIND can be paused for 120 seconds at a time.

Affected Products

• ISC BIND 4.9.5
• ISC BIND 4.9.5 P1
• ISC BIND 4.9.6
• ISC BIND 4.9.7
• ISC BIND 4.9.7 -T1B
• ISC BIND 8.1.0
• ISC BIND 8.1.1
• ISC BIND 8.1.2
• ISC BIND 8.2.0
• ISC BIND 8.2.1
• ISC BIND 8.2.2 P1
• 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
• SGI IRIX 6.5.15
• SGI IRIX 6.5.16
• SGI IRIX 6.5.17
• 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
• Sun Solaris 7.0
• Sun Solaris 7.0_x86

References

• BugTraq: 788
• CERT: CA-1998-05
• CVE: CVE-1999-0833
• URL: http://www.networksorcery.com/enp/protocol/dns.htm
• URL: http://www.faqs.org/rfcs/rfc1123.html
• URL: http://www.freesoft.org/CIE/RFC/1035/index.htm