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Cisco Bug: CSCup62085 - DNS 503 Errors when WSA is under heavy load

Last Modified

Feb 09, 2017

Products (1)

  • Cisco Web Security Appliance

Known Affected Releases

8.0.5-075 8.0.6-053

Description (partial)

A vulnerability in Domain Name System (DNS) resolution in the Cisco Web Security Appliance (WSA) could allow an
unauthenticated, remote attacker to cause a partial denial of service (DoS) condition.

The vulnerability is due to timing consideration when processing DNS requests when under heavy system load. 
An attacker could exploit this vulnerability by sending HTTP traffic to the device which will require DNS resolution. 
An exploit could allow the attacker to cause a partial DoS condition on the affected device.

Default Configuration.
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