USN-297-1: Thunderbird vulnerabilities

14 June 2006

mozilla-thunderbird vulnerabilities

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

  • Ubuntu 6.06 LTS

Software Description


Jonas Sicking discovered that under some circumstances persisted XUL attributes are associated with the wrong URL. A malicious web site could exploit this to execute arbitrary code with the privileges of the user. (MFSA 2006-35, CVE-2006-2775)

Paul Nickerson discovered that content-defined setters on an object prototype were getting called by privileged UI code. It was demonstrated that this could be exploited to run arbitrary web script with full user privileges (MFSA 2006-37, CVE-2006-2776).

Mikolaj Habryn discovered a buffer overflow in the crypto.signText() function. By sending an email with malicious JavaScript to an user, and that user enabled JavaScript in Thunderbird (which is not the default and not recommended), this could potentially be exploited to execute arbitrary code with the user’s privileges. (MFSA 2006-38, CVE-2006-2778)

The Mozilla developer team discovered several bugs that lead to crashes with memory corruption. These might be exploitable by malicious web sites to execute arbitrary code with the privileges of the user. (MFSA 2006-32, CVE-2006-2779, CVE-2006-2780)

Masatoshi Kimura discovered a memory corruption (double-free) when processing a large VCard with invalid base64 characters in it. By sending a maliciously crafted set of VCards to a user, this could potentially be exploited to execute arbitrary code with the user’s privileges. (MFSA 2006-40, CVE-2006-2781)

Masatoshi Kimura found a way to bypass web input sanitizers which filter out JavaScript. By inserting ‘Unicode Byte-order-Mark (BOM)’ characters into the HTML code (e. g. ‘<scr[BOM]ipt>’), these filters might not recognize the tags anymore; however, Thunderbird would still execute them since BOM markers are filtered out before processing a mail containing JavaScript. (MFSA 2006-42, CVE-2006-2783)

Kazuho Oku discovered various ways to perform HTTP response smuggling when used with certain proxy servers. Due to different interpretation of nonstandard HTTP headers in Thunderbird and the proxy server, a malicious HTML email can exploit this to send back two responses to one request. The second response could be used to steal login cookies or other sensitive data from another opened web site. (MFSA 2006-33, CVE-2006-2786)

It was discovered that JavaScript run via EvalInSandbox() can escape the sandbox. Malicious scripts received in emails containing JavaScript could use these privileges to execute arbitrary code with the user’s privileges. (MFSA 2006-31, CVE-2006-2787)

The “enigmail” plugin has been updated to work with the new Thunderbird version.

Update instructions

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

Ubuntu 6.06 LTS
mozilla-thunderbird -
mozilla-thunderbird-enigmail - 2:0.94-0ubuntu4.1

To update your system, please follow these instructions:

After a standard system upgrade you need to restart Thunderbird to effect the necessary changes.

Please note that Thunderbird 1.0.8 in Ubuntu 5.10 and Ubuntu 5.04 are also affected by these problems. Updates for these Ubuntu releases will be delayed due to upstream dropping support for this Thunderbird version. We strongly advise that you disable JavaScript to disable the attack vectors for most vulnerabilities if you use one of these Ubuntu versions.