RHSA-2011:0910 - Security Advisory

Topic

Updated ruby packages that fix three security issues are now available for
Red Hat Enterprise Linux 6.

The Red Hat Security Response Team has rated this update as having moderate
security impact. Common Vulnerability Scoring System (CVSS) base scores,
which give detailed severity ratings, are available for each vulnerability
from the CVE links in the References section.

Description

Ruby is an extensible, interpreted, object-oriented, scripting language. It
has features to process text files and to do system management tasks.

A flaw was found in the way large amounts of memory were allocated on
64-bit systems when using the BigDecimal class. A context-dependent
attacker could use this flaw to cause memory corruption, causing a Ruby
application that uses the BigDecimal class to crash or, possibly, execute
arbitrary code. This issue did not affect 32-bit systems. (CVE-2011-0188)

A race condition flaw was found in the remove system entries method in the
FileUtils module. If a local user ran a Ruby script that uses this method,
a local attacker could use this flaw to delete arbitrary files and
directories accessible to that user via a symbolic link attack.
(CVE-2011-1004)

A flaw was found in the method for translating an exception message into a
string in the Exception class. A remote attacker could use this flaw to
bypass safe level 4 restrictions, allowing untrusted (tainted) code to
modify arbitrary, trusted (untainted) strings, which safe level 4
restrictions would otherwise prevent. (CVE-2011-1005)

Red Hat would like to thank Drew Yao of Apple Product Security for
reporting the CVE-2011-0188 issue.

All Ruby users should upgrade to these updated packages, which contain
backported patches to resolve these issues.

Solution

Before applying this update, make sure all previously-released errata
relevant to your system have been applied.

This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at
https://access.redhat.com/kb/docs/DOC-11259

Affected Products

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.1 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.1 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Desktop 6 i386
• Red Hat Enterprise Linux for IBM z Systems 6 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 6.1 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.1 ppc64
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 i386
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.1 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.1 i386
• Red Hat Virtual Storage Appliance (from RHUI) 6.1 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x

Fixes

• BZ - 678913 - CVE-2011-1004 Ruby: Symlink race condition by removing directory trees in fileutils module
• BZ - 678920 - CVE-2011-1005 Ruby: Untrusted codes able to modify arbitrary strings
• BZ - 682332 - CVE-2011-0188 ruby: memory corruption in BigDecimal on 64bit platforms

CVEs

• CVE-2011-1005
• CVE-2011-0188
• CVE-2011-1004

References

• https://access.redhat.com/security/updates/classification/#moderate
• http://www.ruby-lang.org/en/news/2011/02/18/fileutils-is-vulnerable-to-symlink-race-attacks/
• http://www.ruby-lang.org/en/news/2011/02/18/exception-methods-can-bypass-safe/