Cisco Security Advisory
Cisco IronPort Web Security Appliance AsyncOS SSL Certificate Caching Vulnerability
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AV:A/AC:M/Au:N/C:P/I:P/A:N/E:U/RL:OF/RC:C
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Cisco IronPort Web Security Appliance AsyncOS software contains a vulnerability that could allow an unauthenticated, remote attacker to conduct man-in-the-middle attacks against a targeted system.
The vulnerability is in the insecure SSL implementation of the affected operating system due to improper handling of cached SSL and Transport Layer Security (TLS) certificates. The affected implementation improperly validates client-session traffic using cached certificates.
An unauthenticated, remote attacker could exploit the vulnerability by injecting a newly generated certificate into the server-side session. The attacker would then attempt to convince a targeted user to visit the previously visited domain and establish an SSL connection with the domain. A successful attack could allow the attacker to conduct a man-in-the-middle attack against the targeted user.
Cisco IronPort has confirmed the vulnerability and released software updates.
A successful attack would require the attacker to have access to a network that is adjacent to the targeted user's system. This requirement would limit the likelihood of an attack.
All Cisco IronPort devices are powered by the Cisco IronPort AsyncOS operating system. Additional details on all Cisco IronPort appliances are at the following link: Cisco IronPort AsyncOS
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Cisco IronPort confirmed the vulnerability in bug ID 78906.
This vulnerability was discovered and reported to Cisco by Dell SecureWorks.
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Administrators are advised to apply the appropriate updates.
Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.
Administrators are advised to allow only trusted users to have network access.
Administrators are advised to monitor affected systems.
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Cisco IronPort has made software updates available at the following link: IronPort
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The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
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To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
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Show LessVersion Description Section Status Date 1.0 Initial Release NA Final 2012-Apr-12
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