Functional code that demonstrates an exploit of the Mozilla Firefox and Thunderbird onreadystatechange event code execution vulnerability is publicly available.
A vulnerability in Mozilla Firefox and Thunderbird could allow an unauthenticated, remote attacker to execute arbitrary code on a targeted system.
The vulnerability is due to improper handling of certain web pages by the affected software. An attacker could exploit this vulnerability by convincing a user to visit a malicious web page containing crafted content. If successful, it could allow the attacker to execute arbitrary code on a targeted system or cause the affected software to terminate unexpectedly, resulting in a denial of service (DoS) condition.
Functional code that exploits this vulnerability is available as part of the Metasploit framework.
Mozilla has confirmed this vulnerability and released updated software.
The following Mozilla products are vulnerable:
Firefox versions prior to 22.0
Firefox ESR versions prior to 17.0.7
Thunderbird versions prior to 17.0.7
Thunderbird ESR versions prior to 17.0.7
To exploit the vulnerability, the attacker may provide a link that directs a user to a malicious site and use misleading language or instructions to persuade the user to follow the provided link.
In products such as Thunderbird and SeaMonkey, where scripting is disabled by default, the vulnerability cannot be exploited through the email functionality. However, the browser-like context of these applications is vulnerable to an exploit.
Mozilla has released a security advisory at the following link: MFSA 2013-53
An unauthenticated, remote attacker could exploit this vulnerability to execute arbitrary code on the system with the privileges of the user running the software. The attacker could also exploit this vulnerability to cause the affected software to terminate unexpectedly, leading to a DoS condition.
The vulnerability is due to improper memory operations performed by the affected software while handling certain web pages.
An unauthenticated, remote attacker could exploit this vulnerability by persuading a user to visit a crafted web page with the onreadystatechange event. When the user reloads the page, the affected software could access unmapped memory regions, which may lead to abnormal termination. The attacker could leverage this condition to execute arbitrary code on a targeted system with the privileges of the user running the software.
Administrators are advised to apply the appropriate updates.
Users should verify that unsolicited links are safe to follow.
Users are advised not to open email messages from suspicious or unrecognized sources. If users cannot verify that links or attachments included in email messages are safe, they are advised not to open them.
Administrators are advised to use an unprivileged account when browsing the Internet.
Mozilla has released updated software at the following links:
Red Hat has released updated software for registered subscribers at the following link: Red Hat Network. Red Hat packages can be updated on Red Hat Enterprise Linux versions 5 and later using the yum tool.
Version 2, July 1, 2013, 3:25 PM: FreeBSD has released a VuXML document and updated ports collection to address the Mozilla Firefox and Thunderbird onreadystatechange event code execution vulnerability.
Version 1, June 26, 2013, 4:50 PM: Mozilla Firefox and Thunderbird contain a vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code on the targeted system. Updates are available.
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