Specially crafted DNS packets can compromise the popular Squid web proxy/cache in such a way that it briefly fails to respond. The problem is caused by insufficiently checked DNS responses which Squid initially places in a queue. By sending packets that only contain a header, a queue overflow can be triggered which can apparently be exploited for Denial-of-Service (DoS) attacks.. The flaw can be exploited both from internal clients and from external DNS servers. The problem has been known since the most recent Chaos Communication Congress (26c3), where Fabian Yamaguchi described the details of this, as well as further flaws in other applications, in his presentation entitled "cat /proc/sys/net/ipv4/fuckups"PDF. Versions 2.x, 3.0 up to and including 3.0.STABLE21, and Squid 3.1 up to and including 3.1.0.15 are affected. In versions 3.0.STABLE22 and 3.1.0.16 of Squid, the flaw has been fixed. A patch is also available. The link for this article located at H Security is no longer available. . A vulnerability in the Squid proxy poses risks for DoS attacks through specially designed DNS queries; timely updates are essential for safeguarding.. Squid Proxy, DoS Risk, DNS Exploits. . LinuxSecurity.com Team
Vendors have not issued updates yet for a vulnerability just reported by the Squid Project. "Under some conditions Squid may forward the proxy authentication credentails. This can happen if you normally require your users to log in to use the proxy, but allow some sites to be reached without needing to log in.". . . . Vendors have not issued updates yet for a vulnerability just reported by the Squid Project. "Under some conditions Squid may forward the proxy authentication credentails. This can happen if you normally require your users to log in to use the proxy, but allow some sites to be reached without needing to log in." synopsis under some conditions Squid may forward the proxy authentication credentails. This can happen if you normally require your users to log in to use the proxy, but allow some sites to be reached without needing to log in. This patch restricts such forwarding to only your configured cache_peers. If you need to further control the credentials forwarding then upgrading to Squid-2.5 is recommended as the forwarding is controlled per cache_peer in Squid-2.5 and later. versions 2.4.STABLE6 and earlier platforms All reported by Hernan Otero configuration if a mixture of proxy authentication and sites not requiring authentication is used. patch squid-2.4.STABLE6-proxy_auth.patch workaround If you use proxy authentication, make sure to use it on all requests. Do not allow access to some sites without the need to log in. . Identified flaw in Squid enables unsafe transmission of proxy authentication details in specific scenarios.. Insecure Proxy Authentication, Squid Vulnerability, Credential Management. . LinuxSecurity.com Team
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