Thursday, April 18, 2024

RCE Vulnerability in Millions of Exim Email Server Let Hackers Execute Arbitrary Command & Control the Server Remotely

Critical Remote command execution vulnerability that affected Exim Email Server versions 4.87 to 4.91 let a local attacker or a remote attacker(with limited boundary) can execute an arbitrary command and exploit the server.

Exim is a mail transfer agent which is used on Unix-like operating systems for sending, receiving and routing the email messages. also, it is free software distributed under the terms of the General Public License (GNU)

Both local and remote attacker could exploit this vulnerability, but there are certain non-default configurations restriction take place for the remote attacker in order to execute the arbitrary commands.

RCE means Remote Command Execution, not Remote Code Execution: an attacker can execute arbitrary commands with execv(), as root and there is no memory corruption or ROP (Return-Oriented Programming) is involved in this flaw.

In order to exploit this vulnerability remotely in the default configuration, an attacker must keep a connection to the vulnerable server open for 7 days which can be possible by transmitting one byte every few minutes.

But the complexity of the Exim code, researcher not guaranteed that, it take longer time to exploit but there may be alternative fast method exist.

Exim Email Server are vulnerable by default since its older version 4.87 that was released on April 6, 2016), and the vulnerability was fixed in version 4.92 on Feb 2019.

According to Qualys research, It was not identified as a security vulnerability, and most operating systems are therefore affected. For example, we exploit an up-to-date Debian distribution (9.9) in this advisory.

“We believe that it makes no sense to delay this any longer than that: this vulnerability is trivially exploitable in the local and non-default cases (attackers will have working exploits before that, public or not); and in the default case, a remote attack takes a long time to succeed” OpenWall reported.

This vulnerability referred as “The Return of the WIZard”, is a reference to Sendmail’s ancient WIZ and DEBUG vulnerabilities.

Exim’s maintainers said that there is no evidence that the hole is under active exploitation and that the patch “exists already.

You can follow us on LinkedinTwitterFacebook for daily Cybersecurity updates also you can take the Best Cybersecurity courses online to keep your self-updated.

Also Read: Penetration Testing Mail Server with Email Spoofing – Exploiting Open Relay configured Public Mail Servers


Latest articles

Palo Alto ZeroDay Exploited in The Wild Following PoC Release

Palo Alto Networks has disclosed a critical vulnerability within its PAN-OS operating system, identified...

FIN7 Hackers Attacking IT Employees Of Automotive Industry

IT employees in the automotive industry are often targeted by hackers because they have...

Russian APT44 – The Most Notorious Cyber Sabotage Group Globally

As Russia's invasion of Ukraine enters its third year, the formidable Sandworm (aka FROZENBARENTS,...

SoumniBot Exploiting Android Manifest Flaws to Evade Detection

A new banker, SoumniBot, has recently been identified. It targets Korean users and is...

LeSlipFrancais Data Breach: Customers’ Personal Information Exposed

LeSlipFrancais, the renowned French underwear brand, has confirmed a data breach impacting its customer...

Cisco Hypershield: AI-Powered Hyper-Distributed Security for Data Center

Cisco has unveiled its latest innovation, Cisco Hypershield, marking a milestone in cybersecurity.This groundbreaking...

Phishing-as-a-Service Platform LabHost Seized by Authorities

Authorities have dismantled LabHost, a notorious cybercrime platform that facilitated widespread phishing attacks across...
BALAJI is an Ex-Security Researcher (Threat Research Labs) at Comodo Cybersecurity. Editor-in-Chief & Co-Founder - Cyber Security News & GBHackers On Security.


Mastering WAAP/WAF ROI Analysis

As the importance of compliance and safeguarding critical websites and APIs grows, Web Application and API Protection (WAAP) solutions play an integral role.
Key takeaways include:

  • Pricing models
  • Cost Estimation
  • ROI Calculation

Related Articles