USN-3435-2: Firefox regression

Releases

• Ubuntu 17.04
• Ubuntu 16.04 ESM
• Ubuntu 14.04 ESM

Packages

• firefox - Mozilla Open Source web browser

Details

USN-3435-1 fixed vulnerabilities in Firefox. The update caused the Flash
plugin to crash in some circumstances. This update fixes the problem.

We apologize for the inconvenience.

Original advisory details:

Multiple security issues were discovered in Firefox. If a user were
tricked in to opening a specially crafted website, an attacker could
potentially exploit these to read uninitialized memory, obtain sensitive
information, bypass phishing and malware protection, spoof the origin in
modal dialogs, conduct cross-site scripting (XSS) attacks, cause a denial
of service via application crash, or execute arbitrary code.
(CVE-2017-7793, CVE-2017-7810, CVE-2017-7811, CVE-2017-7812,
CVE-2017-7813, CVE-2017-7814, CVE-2017-7815, CVE-2017-7818, CVE-2017-7819,
CVE-2017-7820, CVE-2017-7822, CVE-2017-7823, CVE-2017-7824)

Martin Thomson discovered that NSS incorrectly generated handshake hashes.
A remote attacker could potentially exploit this to cause a denial of
service via application crash, or execute arbitrary code. (CVE-2017-7805)

Multiple security issues were discovered in WebExtensions. If a user were
tricked in to installing a specially crafted extension, an attacker could
potentially exploit these to download and open non-executable files
without interaction, or obtain elevated privileges. (CVE-2017-7816,
CVE-2017-7821)

Update instructions

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

Ubuntu 17.04

• firefox - 56.0+build6-0ubuntu0.17.04.2

Ubuntu 16.04

• firefox - 56.0+build6-0ubuntu0.16.04.2

Ubuntu 14.04

• firefox - 56.0+build6-0ubuntu0.14.04.2

After a standard system update you need to restart Firefox to make
all the necessary changes.

References

• https://launchpad.net/bugs/1720908