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World's most popular email server hit by security bug

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The world’s most popular mail transfer agent (MTA) has detected a critical bug which would allow hackers to run malicious code with root privileges. The bug was since patched, but until all webmasters upgrade their systems, a realistic threat of a huge data breach exists.

Exim is one of the most widespread mail transfer agent software out there, with a market share of 57 per cent, according to ZDNet. It often comes bundled with different Linux distributions, such as Debian or Red Hat.

All Exim servers running version 4.92.1 or earlier are vulnerable. That means that (not to get too technical) - if the server is configured to accept incoming TLS connections, a hacker could run malicious code with root privileges.

The vulnerability was first spotted by a security researcher named Zerons, back in July. The Exim team was notified, and they have been building a patch ever since, in utmost privacy. That’s because, apparently, the flaw is super easy to exploit. Also, it seems as no one exploited it just yet.

The patch has been issued last Friday, and the problem has since been resolved.

According to BinaryEdge, there are more than 5.2 million Exim servers which are currently running a vulnerable version. This is the second major vulnerability which the Exim team patched this summer, after the “Return of the WIZard” was fixed this June.