What is Mail Server Takeover ?
Mail Server Takeover is a type of security vulnerability that allows attackers to gain unauthorized access to a mail server and take control. This can occur due to various factors such as weak passwords, unpatched software, and social engineering attacks. Attackers can use the compromised server to send spam, intercept email traffic, and steal sensitive information. .
The Story
In 2021, The BBC, one of the largest media organizations in the world, has been vulnerable to mail server takeover. The vulnerability was found by a bug hunter who exploited a broken access vulnerability on the server . According to the write up, the hunter managed to gain access to the BBC’s mail servers by exploiting a series of vulnerabilities that were chained together to create a single, devastating attack. The hunterwas able to gain access to the server through the main domain bbc.co.uk.
The hunter initiated the attack by conducting reconnaissance on BBC’s domains.
He began the recon using SSL names and reverse whois operation techniques to gather all related domains.
Moreover, the hunter sought a general or unique certificate that encompassed most of the domains or SSLs with a limited number of domains.
After extensive research, the hunter discovered a new SSL on Shodan and used it to target the main domain of BBC UK, bbc.co.uk.
Utilizing the Subdomainer automation script, the hunter identified appealing subdomains and proceeded to fuzz them with the help of a dirsearch tool.
To make wordlists for the attack on the BBC Mail Server, the hunter employed a strategic approach.
Starting with a common files wordlist, the hunter identified the web application’s technology and acquired a tailored wordlist.
Subsequently, the hunter pinpointed the specific web app server and used an appropriate wordlist for that server.
Found API Endpoint
In the end, the hunter resorted to the raft wordlists and continued the scan until he found the /api/ endpoint.
At this endpoint, the hunter uncovered unauthorized access to the Admin API, revealing sensitive data such as email addresses and mail user permissions.
With the System_Admin information in hand, the hunter took advantage of a broken access vulnerability on the server, which ultimately led to the compromise of the BBC Mail Server.
Get the BBC Hall of Fame
The hunter was able to compromise over 4 BBC mail servers, and as a result, the hunter name was included in the BBC Hall of Fame.
In conclusion, the BBC’s security breach highlights the importance of regular security checks and patching vulnerabilities.
Organizations must prioritize their security measures to prevent such incidents from happening in the future. It is also a reminder to security professionals to stay vigilant and proactive in their approach to securing their networks and servers.
How to Prevent Mail Server Takeover?
To prevent Mail Server Takeover Vulnerabilities, it is important to ensure that software is up to date with the latest security patches, strong passwords are enforced, and access controls are properly implemented. Additionally, regular security checks and vulnerability assessments should be conducted to identify and address any potential vulnerabilities.
Here are some steps to prevent Mail Server Takeover:
- Keep software up to date: Regularly update software and firmware to ensure that known vulnerabilities are patched.
- Strong passwords: Enforce strong password policies and multi-factor authentication to prevent brute force attacks.
- Access controls: Implement proper access controls and permissions to ensure that only authorized personnel can access sensitive data.
- Conduct regular security checks: Regularly conduct security assessments and vulnerability scans to identify and address any potential vulnerabilities.
- Employee training: Educate employees on best practices for email security and phishing prevention.
By implementing these steps, you can significantly reduce the risk of a Mail Server Takeover and protect your organization’s sensitive information.
Link to full write up: here
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