Please go into detail about how some of the worst self-propagating computer viruses and worms have been tackled by security researchers.

Some of the worst self-propagating computer viruses and worms in history have caused widespread damage and disruption. Security researchers have employed various methods to tackle and mitigate the impact of these threats. Here are some examples of how they have dealt with such notorious viruses and worms:

1. ILOVEYOU (2000): The ILOVEYOU worm, also known as the Love Letter virus, spread through email with a subject line that read "ILOVEYOU" and an attachment titled "LOVE-LETTER-FOR-YOU.TXT.vbs." Upon opening the attachment, the worm would overwrite files, send itself to all contacts in the user's address book, and download a password-stealing application. To tackle the worm, security researchers and antivirus companies quickly developed and distributed updates to their antivirus software to detect and remove the worm. Additionally, email service providers implemented filters to block emails with the ILOVEYOU subject line.

2. Code Red (2001): The Code Red worm exploiteda buffer overflow vulnerability in Microsoft's Internet Information Services (IIS) web server software. The worm would infect a system, deface the website hosted on the server, and then use the compromised system to scan for and infect other vulnerable systems. To combat Code Red, Microsoft released a security patch to fix the vulnerability, and security researchers developed tools to detect and remove the worm from infected systems. Network administrators were urged to apply the patch and implement security measures such as firewalls and intrusion detection systems to prevent further infections.

3. Nimda (2001): Nimda was a complex worm that spread through multiple methods, including email attachments, network shares, and website downloads. It exploited various vulnerabilities in Microsoft's software and caused significant disruption to internet services. Security researchers analyzed the worm's code to understand its behavior and develop effective countermeasures. Antivirus companies updated their software to detect and remove Nimda, while Microsoft released patches to address the vulnerabilities exploited by the worm. Network administrators were advised to the patches, update their antivirus software, and implement security best practices to prevent infections.

4. SQL Slammer (2003): The SQL Slammer worm targeted Microsoft's SQL Server and Desktop Engine (MSDE) database products, causing widespread denial of service attacks and network congestion. The worm exploited a buffer overflow vulnerability in the software. To mitigate the impact of SQL Slammer, Microsoft released a patch to fix the vulnerability, and security researchers developed tools to detect and remove the worm from infected systems. Network administrators were urged to apply the patch, implement firewalls, and monitor network traffic for signs of the worm's activity.

5. Conficker (2008): Conficker, also known as Downadup or Kido, was a sophisticated worm that targeted Windows operating systems and spread through various methods, including exploiting a vulnerability in the system, dictionary attacks on weak passwords, and removable media. The worm created a botnet, which could be used for various malicious purposes, such as launching denial of service attacks or distributing other malware. Security researchers formed the Conficker Working Group, a collaborative effort to analyze the worm and develop countermeasures. Microsoft released a patch to address the vulnerability exploited by Conficker and offered a $250,000 reward for information leading to the arrest and conviction of the worm's creators. Antivirus companies updated their software to detect and remove Conficker, and network administrators were advised to apply the patch, update their antivirus software, and implement security best practices to prevent infections.

In conclusion, security researchers have tackled self-propagating computer viruses and worms by analyzing their code, understanding their behavior, and developing countermeasures such as patches, antivirus updates, and security best practices. Collaboration between researchers, antivirus companies, software vendors, and network administrators has been crucial in mitigating the impact of these threats and preventing further infections.