What should I do if I encounter a malicious DNS attack? Emergency response step guide

in the digital office and the popularity of network services, DNS as a network access "navigation system", once encountered malicious attacks, not only will lead to normal access to the website, user data leakage, but also may lead to business shutdown, brand reputation damage and other chain problems. Many enterprises and individuals in the face of DNS malicious attacks, often due to the lack of emergency plans and miss the best time to deal with. This article from the emergency stop loss, attack investigation, protection reinforcement and other dimensions, for you to sort out a set of landing DNS malicious attack disposal guide, help quickly restore the normal operation of the network.

How to quickly stop losses after DNS malicious attacks?

when it is found that abnormal network access, domain name jump to unfamiliar pages or a large number of invalid requests, the probability is encountered DNS malicious attacks, the first task at this time is to quickly stop loss, to avoid loss expansion.

1, Temporarily switch alternate DNS server

immediately switch the DNS configuration of the device or server to a public trusted backup server, such as domestic 114.114.114.114, Ali's 223.5.5.5, or foreign 8.8.8.8. This move can bypass the original DNS server that has been tampered with or hijacked, quickly restore the basic network access function, and buy time for subsequent investigation.

2 Suspension of non-core network services

for the business affected by DNS malicious attacks, temporarily close the non-core network server level port, limit the external access range, and only retain the necessary communication channels for core business. At the same time, timely notify users of abnormal network conditions to avoid users from leaking sensitive information due to misoperation and reduce the loss of user trust caused by attacks.

How to troubleshoot the specific types of DNS malicious attacks?

quick stop loss, it is necessary to accurately investigate the specific types of DNS malicious attacks in order to formulate follow-up treatment plans in a targeted manner to avoid the recurrence of similar attacks.

1, analysis of network request log location attack characteristics

retrieve the access logs of DNS servers, firewalls and business servers, focusing on whether there are a large number of duplicate domain name resolution requests, abnormal Internet Protocol Address jump records, or high-frequency requests from the same IP segment. For example, DNS amplification attacks will show the characteristics of small request data packets and large response data packets, while DNS hijacking will show that the domain name resolution results do not match the official IP.

2, check DNS cache and resolution record integrity

check the cache records of the local device and DNS server to confirm whether there are unfamiliar domain name resolution entries; at the same time log in to the background of the domain name registrar to check whether the A records, MX records and other resolution configurations of the domain name have been tampered with. If abnormal records are found, they need to be deleted immediately and restored to the official correct configuration to block the continuous impact of DNS malicious attacks.

How to strengthen the system and network after DNS malicious attack?

complete the attack investigation and temporary recovery, the system and network must be fully reinforced to improve the ability to resist DNS malicious attacks from the root cause.

1, open DNSSEC domain name security extension

DNSSEC can verify the authenticity and integrity of domain name resolution records through digital signature technology, and effectively prevent DNS malicious attacks such as DNS cache poisoning and domain name hijacking. Contact the domain name registrar to open the DNSSEC service and configure the corresponding signature information on the DNS server to ensure that the resolution records obtained by users are from official authorization.

2, deploy DNS firewall and traffic cleaning service

deploy a professional DNS firewall at the network entrance, real-time detection of all DNS requests, interception of abnormal requests, malicious domain names and forged resolution responses; for high-traffic services, access to third-party traffic cleaning services, with its large bandwidth and intelligent identification capabilities, filtering DNS malicious attacks generated massive invalid traffic, to ensure the normal operation of the core business.

3, regularly update the system and DNS software patches

install security patches for operating systems and DNS server software in a timely manner to fix known vulnerabilities. Many DNS malicious attacks are launched using unpatched system vulnerabilities. Keeping the software version up to date can greatly reduce the risk of being attacked.

four, how to optimize the DNS malicious attack response system through replay?

every DNS malicious attack is an actual exercise, through the review summary can improve its own emergency response system, improve the future defense efficiency.

1, sorting out the shortcomings of the whole process of attack disposal

review the handling process of this DNS malicious attack, analyze the problems existing in the stop loss speed, troubleshooting accuracy, reinforcement timeliness, etc., such as whether the delay is caused by incomplete information of the backup DNS server, or the failure to quickly locate the source of the attack due to incomplete log records. For these deficiencies, timely supplement and improve the details of the emergency plan.

2, conduct regular DNS malicious attack simulation exercises

according to the optimized emergency plan, regularly organize internal technical teams to carry out DNS malicious attack simulation drills, simulate different types of attack scenarios, and test the team's response speed, disposal ability and effectiveness of protective measures. Through drills, the team is familiar with the disposal process and can calmly deal with real attacks.

To sum up, in the face of DNS malicious attacks, it is necessary to follow the whole process response logic of "quick stop loss - accurate investigation - comprehensive reinforcement - review optimization", from emergency response to long-term protection to form a closed loop. Through scientific disposal methods, not only can the loss be quickly reduced when the attack occurs, but also the anti-attack ability of the network system can be gradually improved, and the security line of defense can be built for the stable operation of the business.