RHSA-2011:0558 - Security Advisory

Topic

Updated perl packages that fix three security issues and several bugs 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

Perl is a high-level programming language commonly used for system
administration utilities and web programming. The Perl CGI module provides
resources for preparing and processing Common Gateway Interface (CGI) based
HTTP requests and responses.

It was found that the Perl CGI module used a hard-coded value for the MIME
boundary string in multipart/x-mixed-replace content. A remote attacker
could possibly use this flaw to conduct an HTTP response splitting attack
via a specially-crafted HTTP request. (CVE-2010-2761)

A CRLF injection flaw was found in the way the Perl CGI module processed a
sequence of non-whitespace preceded by newline characters in the header. A
remote attacker could use this flaw to conduct an HTTP response splitting
attack via a specially-crafted sequence of characters provided to the CGI
module. (CVE-2010-4410)

It was found that certain Perl string manipulation functions (such as uc()
and lc()) failed to preserve the taint bit. A remote attacker could use
this flaw to bypass the Perl taint mode protection mechanism in scripts
that use the affected functions to process tainted input. (CVE-2011-1487)

These packages upgrade the CGI module to version 3.51. Refer to the CGI
module's Changes file, linked to in the References, for a full list of
changes.

This update also fixes the following bugs:

• When using the "threads" module, an attempt to send a signal to a thread

that did not have a signal handler specified caused the perl interpreter to
terminate unexpectedly with a segmentation fault. With this update, the
"threads" module has been updated to upstream version 1.82, which fixes
this bug. As a result, sending a signal to a thread that does not have the
signal handler specified no longer causes perl to crash. (BZ#626330)

• Prior to this update, the perl packages did not require the Digest::SHA

module as a dependency. Consequent to this, when a user started the cpan
command line interface and attempted to download a distribution from CPAN,
they may have been presented with the following message:

CPAN: checksum security checks disabled because Digest::SHA not installed.
Please consider installing the Digest::SHA module.

This update corrects the spec file for the perl package to require the
perl-Digest-SHA package as a dependency, and cpan no longer displays the
above message. (BZ#640716)

• When using the "threads" module, continual creation and destruction of

threads could cause the Perl program to consume an increasing amount of
memory. With this update, the underlying source code has been corrected to
free the allocated memory when a thread is destroyed, and the continual
creation and destruction of threads in Perl programs no longer leads to
memory leaks. (BZ#640720)

• Due to a packaging error, the perl packages did not include the

"NDBM_File" module. This update corrects this error, and "NDBM_File" is now
included as expected. (BZ#640729)

• Prior to this update, the prove(1) manual page and the "prove --help"

command listed "--fork" as a valid command line option. However, version
3.17 of the Test::Harness distribution removed the support for the
fork-based parallel testing, and the prove utility thus no longer supports
this option. This update corrects both the manual page and the output of
the "prove --help" command, so that "--fork" is no longer included in the
list of available command line options. (BZ#609492)

Users of Perl, especially those of Perl threads, are advised to upgrade to
these updated packages, which correct 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 Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• 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 Power, big endian 6 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 Life Cycle Support (for IBM z Systems) 6 s390x

Fixes

• BZ - 609492 - unknown option fork with prove
• BZ - 626330 - Sending signal to thread without signal handler in thread causes perl to segfault
• BZ - 640716 - Let perl-CPAN Require: perl(Digest::SHA)
• BZ - 640720 - Thread desctructor leaks
• BZ - 640729 - NDBM_File module is missing in perl core
• BZ - 658976 - perl-CGI, perl-CGI-Simple: CVE-2010-2761 - hardcoded MIME boundary value for multipart content, CVE-2010-4410 - CRLF injection allowing HTTP response splitting
• BZ - 692898 - CVE-2011-1487 perl: lc(), uc() routines are laundering tainted data

CVEs

• CVE-2011-1487
• CVE-2010-2761
• CVE-2010-4410

References

• https://access.redhat.com/security/updates/classification/#moderate
• http://cpansearch.perl.org/src/MARKSTOS/CGI.pm-3.51/Changes