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TITLE:
Cisco Various Products ICMP Message Handling Denial of Service

SECUNIA ADVISORY ID:
SA14904

VERIFY ADVISORY:
http://secunia.com/advisories/14904/

CRITICAL:
Less critical

IMPACT:
DoS

WHERE:
>From remote

OPERATING SYSTEM:
Cisco Content Services Switch 11000 Series (WebNS)
http://secunia.com/product/1507/
Cisco Global Site Selector (GSS) 4480 1.x
http://secunia.com/product/2270/
Cisco IOS 10.x
http://secunia.com/product/184/
Cisco IOS 11.x
http://secunia.com/product/183/
Cisco IOS 12.x
http://secunia.com/product/182/
Cisco IOS R11.x
http://secunia.com/product/53/
Cisco IOS R12.x
http://secunia.com/product/50/
Cisco IOS XR (CRS-1) 3.x
http://secunia.com/product/4907/
Cisco ONS 15000 Series
http://secunia.com/product/684/
Cisco PIX 6.x
http://secunia.com/product/56/
Cisco SAN-OS 1.x (MDS 9000 Switches)
http://secunia.com/product/3214/

DESCRIPTION:
Fernando Gont has published an Internet-Draft describing how ICMP
(Internet Control Message Protocol) can be exploited by malicious
people to cause a DoS (Denial of Service). Cisco has acknowledged
that various Cisco products are affected.

The published Internet-Draft details three types of attacks, which
utilize the following ICMP messages to cause a negative impact on TCP
connections either terminating or originating from a vulnerable
device.

1) ICMP "hard" error messages
2) ICMP "fragmentation needed and Don't Fragment (DF) bit set"
messages (known as PMTUD attacks)
3) ICMP "source quench" messages

These attacks can all be exploited to cause TCP connection resets,
reduce the throughput in existing TCP connections, or consume large
amounts of CPU and memory resources.

NOTE: See the original advisory for a list of affected versions.

SOLUTION:
See patch matrix in vendor advisory for information about fixes.
http://www.cisco.com/warp/public/707/cisco-sa-20050412-icmp.shtml#software

PROVIDED AND/OR DISCOVERED BY:
Fernando Gont

ORIGINAL ADVISORY:
Cisco:
http://www.cisco.com/warp/public/707/cisco-sa-20050412-icmp.shtml

NISCC:
http://www.niscc.gov.uk/niscc/docs/al-20050412-00308.html

ICMP attacks against TCP:
http://www.gont.com.ar/drafts/icmp-attacks-against-tcp.html

OTHER REFERENCES:
RFC1122 (Requirements for Internet Hosts -- Communication Layers):
http://www.ietf.org/rfc/rfc1122.txt

RFC1191 (Path MTU Discovery):
http://www.ietf.org/rfc/rfc1191.txt

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About:
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