Wednesday, June 19, 2024

Exim Vulnerability Puts More than 500,000 Email Servers at High Risk

A critical vulnerability with Exim email servers put’s more than 500,000 servers at risk. The bug affects all the version of Exim from the first commit to last 3.x release.

The Vulnerability resides with b64decode function in the SMTP listener. When the provided input is not a valid base64 string it consumes additional bytes while decoding which causes the one-byte heap overflow.

Taiwanese security Researcher Meh discovered the vulnerability. He says generally this bug is not critical, but with Exim, it overwrites the critical data when the string fits some specific length and also the extra byte is controllable which make the exploitation more feasible.

Exim uses base64 encoding to communicate with the clients and the encodes functions will be stored in a buffer that allocated by store_get(). To leverage the one-byte heap overflow Meh selected sender_host_name as a better choice.

Also Read Operation Honeybee – A Cyber Attack Leveraging an SYSCON Backdoor Using MS Word Documents

Meh published a blog post describing the vulnerability along with the steps to exploit it. According to the recent Mail (MX) Server Survey, around 56 Percent servers running Exim.

The bug was tracked as CVE-2018-6789, an attacker could leverage the vulnerability by sending a crafted malicious request that causes the buffer overflow and it can use to execute the remote code.

Exim email servers – Patch

Meh reported the vulnerability to Exim and the Exim released version 4.90.1, which fixes the vulnerability. Users are advised to update their Exim server version to 4.90.1 or above.

Website

Latest articles

Amtrak Data Breach: Hackers Accessed User’s Email Address

Amtrak notified its customers regarding a significant security breach involving its Amtrak Guest Rewards...

Chrome Security Update – Patch for 6 Vulnerabilities

Google has announced a new update for the Chrome browser, rolling out version 126.0.6478.114/115...

Hackers Weaponize Windows Installer (MSI) Files to Deliver Malware

Cybersecurity researchers have uncovered a sophisticated malware campaign orchestrated by a threat actor group,...

Hackers Using VPNs To Exploit Restrictions & Steal Mobile Data

Hackers are offering "free" mobile data access on Telegram channels by exploiting loopholes in...

New PhaaS Platform Lets Attackers Bypass Two-Factor Authentication

Several phishing campaign kits have been used widely by threat actors in the past....

Stuxnet, The Malware That Propagates To Air-Gapped Networks

Stuxnet, a complex worm discovered in 2010, targeted Supervisory Control and Data Acquisition (SCADA)...

Threat Actors Claiming Breach of AMD Source Code on Hacking Forums

A threat actor named " IntelBroker " claims to have breached AMD in June...
Guru baran
Guru baranhttps://gbhackers.com
Gurubaran is a co-founder of Cyber Security News and GBHackers On Security. He has 10+ years of experience as a Security Consultant, Editor, and Analyst in cybersecurity, technology, and communications.

Free Webinar

API Vulnerability Scanning

71% of the internet traffic comes from APIs so APIs have become soft targets for hackers.Securing APIs is a simple workflow provided you find API specific vulnerabilities and protect them.In the upcoming webinar, join Vivek Gopalan, VP of Products at Indusface as he takes you through the fundamentals of API vulnerability scanning..
Key takeaways include:

  • Scan API endpoints for OWASP API Top 10 vulnerabilities
  • Perform API penetration testing for business logic vulnerabilities
  • Prioritize the most critical vulnerabilities with AcuRisQ
  • Workflow automation for this entire process

Related Articles