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Ubuntu: Security update for Lynx

Dan Rosenberg discovered a heap-based buffer overflow in Lynx. If a user were tricked into opening a specially crafted page, a remote attacker could cause a denial of service via application crash, or possibly execute arbitrary code as the user invoking the program. It was discovered that Lynx did not properly verify that an HTTPS certificate was signed by a trusted certificate authority. This could allow an attacker to perform a “man in the middle” (MITM) attack which would make the user believe their connection is secure, but is actually being monitored. This update changes the behavior of Lynx such that self-signed certificates no longer validate. Users requiring the previous behavior can use the FORCE_SSL_PROMPT option in lynx.cfg.

Updated packages are available from security.ubuntu.com.

==========================================================================
Ubuntu Security Notice USN-1642-1
November 29, 2012

lynx-cur vulnerabilities
==========================================================================

A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 12.10
- Ubuntu 12.04 LTS
- Ubuntu 11.10
- Ubuntu 10.04 LTS

Summary:

Two security issues were fixed in Lynx.

Software Description:
- lynx-cur: Text-mode WWW Browser with NLS support

Details:

Dan Rosenberg discovered a heap-based buffer overflow in Lynx. If a user
were tricked into opening a specially crafted page, a remote attacker could
cause a denial of service via application crash, or possibly execute
arbitrary code as the user invoking the program. This issue only affected
Ubuntu 10.04 LTS. (CVE-2010-2810)

It was discovered that Lynx did not properly verify that an HTTPS
certificate was signed by a trusted certificate authority. This could allow
an attacker to perform a "man in the middle" (MITM) attack which would make
the user believe their connection is secure, but is actually being
monitored. This update changes the behavior of Lynx such that self-signed
certificates no longer validate. Users requiring the previous behavior can
use the 'FORCE_SSL_PROMPT' option in lynx.cfg. (CVE-2012-5821)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 12.10:
 lynx-cur                        2.8.8dev.12-2ubuntu0.1

Ubuntu 12.04 LTS:
 lynx-cur                        2.8.8dev.9-2ubuntu0.12.04.1

Ubuntu 11.10:
 lynx-cur                        2.8.8dev.9-2ubuntu0.11.10.1

Ubuntu 10.04 LTS:
 lynx-cur                        2.8.8dev.2-1ubuntu0.1

In general, a standard system update will make all the necessary changes.

References:
 http://www.ubuntu.com/usn/usn-1642-1
 CVE-2010-2810, CVE-2012-5821

Package Information:
 https://launchpad.net/ubuntu/+source/lynx-cur/2.8.8dev.12-2ubuntu0.1
 https://launchpad.net/ubuntu/+source/lynx-cur/2.8.8dev.9-2ubuntu0.12.04.1
 https://launchpad.net/ubuntu/+source/lynx-cur/2.8.8dev.9-2ubuntu0.11.10.1
 https://launchpad.net/ubuntu/+source/lynx-cur/2.8.8dev.2-1ubuntu0.1
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