Mastodon Releases Security Update to Fix Critical Vulnerabilities

Mastodon, the decentralized social network that has gained popularity after the latest Twitter changes, has released a security update to fix critical vulnerabilities that could put millions of users at risk. The most serious problem was called TootRoot and forced the media processing code in Mastodon to create files in an arbitrary location.

TootRoot Vulnerability

The TootRoot vulnerability has been identified as CVE-2023-36460. The developers described this problem as “arbitrary creation of files with media attachments”.
Well-known information security expert Kevin Beaumont writes that exploitation of the vulnerability allowed the creation and posting of “a message that creates a web shell for instances that process this message.” It was he who came up with the name TootRoot for the vulnerability: posts in Mastodon are called toots (by analogy with tweets on Twitter), and it was user messages that made it possible to gain root access to instances.

Potential Damage

Experts explain that an attacker controlling thousands of Mastodon instances could cause damage to both individual users and the Internet as a whole. For example, hijacked instances could send messages to users instructing them to download and install malicious applications, or they could cause the entire infrastructure to crash.
The patches released this week are the result of a recent Mastodon security audit and pentest funded by the Mozilla Foundation. Social media co-founder and CTO Renaud Chaput told media that the audit was done by a firm called Cure53 and the fixes were developed by a team inside Mastodon. As a result, in recent weeks, developers have sent notifications to all major servers, informing their administrators to install the update as soon as when it becomes available.

Other Vulnerabilities

A total of five vulnerabilities have been fixed in Mastodon, and another of the bugs, CVE-2023-36459, has also been given critical status. The Mastodon review describes this shortcoming as an XSS issue related to oEmbed preview.
“Using carefully crafted oEmbed data, an attacker could bypass Mastodon’s HTML scraping and inject arbitrary HTML into oEmbed preview cards. This creates an XSS payload delivery vector that can be rendered in the user’s browser after clicking on a malicious link.
The three remaining vulnerabilities are of lower severity. Among them: blind LDAP login injection; denial of service through slow HTTP responses; and an issue with formatting links to verified profiles.
Mastodon has released the security update to fix these critical vulnerabilities and protect its millions of users. It is important for all users to install the update as soon as possible to ensure their safety.