__________________________________________________________________ Squid Proxy Cache Security Update Advisory SQUID-2011:2 __________________________________________________________________ Advisory ID: SQUID-2011:2 Date: August 27, 2010 Summary: Password truncation in NCSA using DES Affected versions: Squid 3.0 -> 3.0.STABLE25 Squid 3.1 -> 3.1.14 Squid 3.2 -> 3.2.0.10 Fixed in version: Squid 3.2.0.11, 3.1.15, 3.0.STABLE26 __________________________________________________________________ http://www.squid-cache.org/Advisories/SQUID-2011_2.txt __________________________________________________________________ Problem Description: DES algorithm implemented by htpasswd and crypt() in some popular encryption libraries silently truncates passwords. Squid NCSA authentication helper permits long and complex passwords to be used with DES despite this well known issue. Leaving users with a false view of their security. __________________________________________________________________ Severity: This problem hides potential security issues and allows attackers to bypass security controls relying on long and hard to guess passwords. __________________________________________________________________ Updated Packages: This bug is fixed by Squid version 3.2.0.11. Squid version 3.1.15 and 3.0.STABLE26 contain a partial fix. To allow a period of transition for administrators of large networks this release contains a helper which ALERTS in cache.log but does not block user logins. In addition, patches addressing this problem can be found in our patch archives. Squid 3.0: (transitional protection) http://www.squid-cache.org/Versions/v3/3.1/changesets/squid-3.0-9194.patch Squid 3.1: (transitional protection) http://www.squid-cache.org/Versions/v3/3.1/changesets/squid-3.1-10356.patch Squid 3.2: (full protection) http://www.squid-cache.org/Versions/v3/3.2/changesets/squid-3.2-11271.patch If you are using a prepackaged version of Squid then please refer to the package vendor for availability information on updated packages. __________________________________________________________________ Determining if your version is vulnerable: Squid and its cache are not harmed by this vulnerability. The issue is limited to the NCSA helper and potential third-party access to protected resources. ncsa_auth or basic_ncsa_auth helpers bundled with Squid releases up to 3.2.0.11 are vulnerable. The helpers bundled with 3.1.15 and 3.0.STABLE26 will warn loudly when this vulnerability is encountered by any user, but will allow login to proceed. Manual vulnerability test of the helper: * create a user account with 9-character password: # htpasswd -b /test test 123456789 * run the helper and enter the test credentials, both truncated to 8 characters and in full: # ncsa_auth /test test 12345678 test 123456789 If the helper produces "OK" to both of these it is vulnerable. If the helper produces "ERR" to either one it is not vulnerable. The htpasswd -m option affects the vulnerability. When -m is used long passwords are stored in a more secure MD5 hash which is not vulnerable. __________________________________________________________________ Workarounds: Use the -m option on htpasswd when encrypting credentials. Ensuring that MD5 encryption is used by all tools updating the credentials file. The most secure implementation of these requirements is to use salted MD5 with magic strings to encrypt the passwords. __________________________________________________________________ Contact details for the Squid project: For installation / upgrade support on binary packaged versions of Squid: Your first point of contact should be your binary package vendor. If your install and build Squid from the original Squid sources then the squid-users@squid-cache.org mailing list is your primary support point. For subscription details see . For reporting of non-security bugs in the latest STABLE release the squid bugzilla database should be used . For reporting of security sensitive bugs send an email to the squid-bugs@squid-cache.org mailing list. It's a closed list (though anyone can post) and security related bug reports are treated in confidence until the impact has been established. __________________________________________________________________ Credits: The vulnerability was reported by Gaiar Mukhetdinov "Indarien" __________________________________________________________________ Revision history: 2011-08-27 11:05 GMT Initial Version 2011-08-27 17:31 GMT Update to include 3.0.STABEL26 release 2011-08-29 07:39 GMT Update reporter name __________________________________________________________________ END