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21Nails Exim RCE Vulnerabilities

Exim has released security updates to address multiple critical vulnerabilities discovered by security researchers. There are no known public exploits targeting these vulnerabilities at the time of publication.

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Summary

Exim has released security updates to address multiple critical vulnerabilities discovered by security researchers. There are no known public exploits targeting these vulnerabilities at the time of publication.


Affected platforms

The following platforms are known to be affected:

Threat details

Introduction

Exim has released security updates to address multiple critical vulnerabilities known as '21Nails' discovered by security researchers. A remote attacker could exploit these vulnerabilities to achieve remote code execution (RCE) with elevated privileges on Exim mail servers.


Vulnerabilities

The vulnerabilities appear to arise from flaws in memory management that can be exploited to gain initial access to the remote Exim server. Privileges can then be escalated by exploiting a component of the Exim software that runs with root permissions.

There are no known public exploits targeting these vulnerabilities at the time of publication.


Threat updates

Date Update
10 May 2021 Center for Internet Security Advisory

Center for Internet Security has released Advisory 2021-064 providing more information, including a technical summary of the vulnerabilities in Exim mail transfer agent and recommendations of actions to be taken to address these.


Remediation advice

Users and administrators are encouraged to review Exim's security advisory and immediately update to version 4.94.2 or higher. The update may usually be found and installed using the system's package manager.


Last edited: 10 May 2021 3:06 pm