RHSA-2013:0714 - Security Advisory

Topic

An updated stunnel package that fixes one security issue is now available
for Red Hat Enterprise Linux 6.

The Red Hat Security Response Team has rated this update as having moderate
security impact. A Common Vulnerability Scoring System (CVSS) base score,
which gives a detailed severity rating, is available from the CVE link in
the References section.

Description

stunnel is a socket wrapper which can provide SSL (Secure Sockets Layer)
support to ordinary applications. For example, it can be used in
conjunction with imapd to create an SSL-secure IMAP server.

An integer conversion issue was found in stunnel when using Microsoft NT
LAN Manager (NTLM) authentication with the HTTP CONNECT tunneling method.
With this configuration, and using stunnel in SSL client mode on a 64-bit
system, an attacker could possibly execute arbitrary code with the
privileges of the stunnel process via a man-in-the-middle attack or by
tricking a user into using a malicious proxy. (CVE-2013-1762)

All stunnel users should upgrade to this updated package, which contains a
backported patch to correct this issue.

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/knowledge/articles/11258

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 6.4 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.4 i386
• Red Hat Enterprise Linux Server - AUS 6.4 x86_64
• 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 6.4 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 6.4 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 6.4 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.4 i386
• Red Hat Gluster Storage Server for On-premise 2.1 x86_64
• Red Hat Storage for Public Cloud (via RHUI) 2.1 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x
• 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 - 917839 - CVE-2013-1762 Stunnel: buffer overflow vulnerability due to incorrect integer conversion in the NTLM authentication of the CONNECT protocol negotiation

CVEs

• CVE-2013-1762

References

• https://access.redhat.com/security/updates/classification/#moderate
• https://www.stunnel.org/CVE-2013-1762.html