Blue Coat Systems Information for VU#637934

TCP does not adequately validate segments before updating timestamp value

Status

Affected

Vendor Statement

No statement is currently available from the vendor regarding this vulnerability.

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.

Vendor References

None

Addendum

Security Advisory: TCP Vulnerability CAN-2005-0356

Date:
June 28, 2005

Severity:
High

Description:
Some Blue Coat Systems products are vulnerable to the attack described in CAN-2005-0356. This is a denial of service vulnerability that exists for TCP RFC 1323. The issue exists in the Protection Against Wrapped Sequence Numbers (PAWS) technique when TCP PAWS is configured to employ timestamp values.

A successful attack may result in a TCP connection to drop packets, resulting is a denial of service situation.

Affected Systems:
All OS Releases (CacheOS, SGOS)

Workaround:
Disable rfc-1323 support

SG3/SG4

#(config)tcp-ip rfc-1323 disable

SG2

#(config) reveal-advanced tcp-ip
#(config) tcp-ip no rfc-1323

Fixed in:
SG3.2.5 (TBD)
SG4.1.2 (TBD)

Additional Information:
http://www.kb.cert.org/vuls/id/637934
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2005-0356

For more information, please contact the Blue Coat Technical Support Department.

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