RHSA-2011:1088 - Security Advisory

Topic

Updated systemtap packages that fix two 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

SystemTap is an instrumentation system for systems running the Linux
kernel. The system allows developers to write scripts to collect data on
the operation of the system.

It was found that SystemTap did not perform proper module path sanity
checking if a user specified a custom path to the uprobes module, used
when performing user-space probing ("staprun -u"). A local user who is a
member of the stapusr group could use this flaw to bypass intended
module-loading restrictions, allowing them to escalate their privileges by
loading an arbitrary, unsigned module. (CVE-2011-2502)

A race condition flaw was found in the way the staprun utility performed
module loading. A local user who is a member of the stapusr group could
use this flaw to modify a signed module while it is being loaded,
allowing them to escalate their privileges. (CVE-2011-2503)

SystemTap users should upgrade to these updated packages, which contain
backported patches to 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 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 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 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 Life Cycle Support (for IBM z Systems) 6 s390x
• 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 Extension 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension (for IBM z Systems) 6 s390x

Fixes

• BZ - 716476 - CVE-2011-2502 systemtap: insufficient security check when loading uprobes kernel module
• BZ - 716489 - CVE-2011-2503 systemtap: signed module loading race condition

CVEs

• CVE-2011-2502
• CVE-2011-2503

References

• https://access.redhat.com/security/updates/classification/#moderate