Red Hat: squid ACL escape vulnerability
Summary
Summary
Squid is a full-featured Web proxy cache.A bug was found in the processing of %-encoded characters in a URL inversions of Squid 2.5.STABLE4 and earlier. If a Squid configuration usesAccess Control Lists (ACLs), a remote attacker could create URLs that wouldnot be correctly tested against Squid's ACLs, potentially allowing clientsto access prohibited URLs.Users of Squid should update to these erratum packages which are notvulnerable to this issue.In addition, these packages contain a new Access Control type, "urllogin",which can be used to protect vulnerable Microsoft Internet Explorer clientsfrom accessing URLs that contain login information. Such URLs are oftenused by fraudsters to trick web users into revealing valuable personal data.Note that the default Squid configuration does not make use of this newaccess control type. You must explicitly configure Squid with ACLs thatuse this new type, in accordance with your own site policies.
Solution
Before applying this update, make sure all previously released errata
relevant to your system have been applied.
To update all RPMs for your particular architecture, run:
rpm -Fvh [filenames]
where [filenames] is a list of the RPMs you wish to upgrade. Only those
RPMs which are currently installed will be updated. Those RPMs which are
not installed but included in the list will not be updated. Note that you
can also use wildcards (*.rpm) if your current directory *only* contains the
desired RPMs.
Please note that this update is also available via Red Hat Network. Many
people find this an easier way to apply updates. To use Red Hat Network,
launch the Red Hat Update Agent with the following command:
up2date
This will start an interactive process that will result in the appropriate
RPMs being upgraded on your system.
If up2date fails to connect to Red Hat Network due to SSL
Certificate Errors, you need to install a version of the
up2date client with an updated certificate. The latest version of
up2date is available from the Red Hat FTP site and may also be
downloaded directly from the RHN website:
https://access.redhat.com
5. RPMs required:
Red Hat Linux 9:
SRPMS:
i386:
6. Verificationx:
MD5 sum Package Name
3a78ab4b0423bdbfc5b6bb36897b78ce 9/en/os/SRPMS/squid-2.5.STABLE1-3.9.src.rpm
348ca4845204fadad07116be64d9767e 9/en/os/i386/squid-2.5.STABLE1-3.9.i386.rpm
These packages are GPG signed by Red Hat for security. Our key is
available from https://www.redhat.com/security/keys.html
You can verify each package with the following command:
rpm --checksig -v
If you only wish to verify that each package has not been corrupted or
tampered with, examine only the md5sum with the following command:
md5sum
References
Package List
Topic
Topic
An updated squid package is avaliable that fixes a security vulnerability in
URL decoding and provides a new ACL type for protecting vulnerable clients.
Relevant Releases Architectures
Red Hat Linux 9 - i386
Bugs Fixed