Table of contents
1. How to troubleshoot Windows intrusion?
2. How to troubleshoot Linux intrusion?
3. What are the commonly used troubleshooting commands in Linux?
4. What are the troubleshooting ideas for emergency response?
6. Do you know how to check Java memory horses?
7. Given a relatively large log, how should it be analyzed?
8. How to analyze the proxied data flow?
9. After being attacked, how to troubleshoot if the log files and horseback files are deleted?
10. How to trace the source of traffic through the wireshark tool?
11. Several servers on the intranet, one of them was penetrated, how to troubleshoot?
1. Windows intrusion troubleshooting ideas?
1. Collect information : collect information related to system security, including log files, process lists, network connections, system configuration, etc.
2. Analyze information : analyze the collected information to determine abnormal behavior and potential threats.
3. Confirm the threat : confirm the threat exists in the system, and determine its type and degree.
4. Prevent attacks : Take corresponding measures to stop attacks as soon as possible and reduce losses.
5. Restore the system : restore the attacked system to ensure its normal operation.
Several methods of intrusion troubleshooting:
1. Use antivirus software : Regularly use antivirus software to scan the system to discover and remove potential threats in time.
2. Regularly update the system : regularly update the system and security patches to ensure the security of the system.
3. Monitor network connections : monitor network connections, discover abnormal connections and traffic, and illegal access attempts in a timely manner.
4. Analyze log files : analyze log files to understand system usage and abnormal behavior, and detect threats in time.
5. Use security tools : Use security tools, such as intrusion detection systems, network monitoring systems, etc., to help discover and block threats.
6. Strengthen user education : strengthen user education, improve user security awareness, and reduce the impact of human factors on system security.
2. Linux intrusion troubleshooting ideas?
1. Collect basic information : collect system version, configuration files, logs and other information
2. Analyze unusual behavior : such as unusual processes, network traffic, or file changes.
3. Confirm the intrusion point : determine the way the attacker may intrude, and check whether there are unfixed vulnerabilities.
4. Isolate the infected system : Isolate the infected system in a timely manner to limit damage and avoid further spread.
5. Restore the system : remove malicious codes and repair damaged parts, and restore data and configuration files through backup to ensure system security.
6. Collect evidence : collect detailed information on intrusion events, including the time of the attack, the method of intrusion, the scope of the impact, and the loss situation.
3. Linux intrusion troubleshooting ideas?
1. top: Displays the processes that occupy the most CPU and memory in the current system.
2. ps: Displays a list of all running processes in the current system.
3. netstat: Displays network connection status and statistical information, such as open ports, TCP/UDP connections, and network interfaces.
4. ifconfig/iwconfig: Display the status and configuration information of the network interface.
5. Ping/traceroute: A tool for testing network connectivity and detecting network failures.
6. df/du: Display disk usage, including information such as used space and free space.
7. ls/lsof: used to view open files, directories and file descriptors.
8. strace/ltrace: trace system calls and library function calls during application execution.
9. tcpdump: captures network packets and records them in log files for subsequent analysis.
10. tail: Monitor log files in real time and display the latest added log information.
4. What are the troubleshooting ideas for emergency response?
1. Confirm the event : First, you need to understand the specific circumstances of the event, including the time of occurrence, scope of impact, affected systems and services, and other information. At the same time, it is also necessary to determine whether there are phishing emails, virus infections, etc., to determine whether there are network security incidents.
2. Collect evidence : After confirming the security incident, relevant evidence needs to be collected in time, including log records, network traffic, process information, file system status and other information, and archived and backed up. These evidences can provide a basis for subsequent analysis.
3. Analyzing data : Analyzing collected evidence, especially data such as logs and network traffic, can help quickly locate problems and confirm whether there is an attack. Common tools in the analysis process, Wireshark, Nmap, Sysinternals, etc.
4. Prevent attacks : After confirming the existence of attacks, immediate measures need to be taken to prevent attacks and protect existing systems. These measures include blocking the network, isolating infected hosts, closing vulnerabilities, and more.
5. Formulate emergency plans : According to the analysis results, formulate corresponding emergency plans to ensure that the system can quickly return to normal operation. Contingency plans should include recovering data, fixing vulnerabilities, and strengthening security defenses.
5. How to detect webshell?
Webshell refers to a command execution environment embedded in a web server, which can interact with it through web pages or HTTP protocol, and attackers can use webshell to perform various malicious operations .
The following methods can be used to detect webshells:
1. View the web server access log : Webshells usually generate abnormal network traffic, such as sending POST requests to non-standard ports. Check the access logs of the web server to see if there are any abnormal requests.
2. Security scanning tool : Use a security scanning tool to scan the web server to detect whether there is a webshell. Commonly used security scanning tools include Nessus, OpenVAS, etc.
3. File monitoring : Webshells usually write malicious code into a certain file, so file monitoring tools can be used to detect Webshells. For example, a file monitoring tool sends an alert immediately when a file is modified.
4. Memory monitoring : Some advanced webshells may not leave any traces on the disk, but directly inject code into the memory. Therefore, use memory monitoring tools to detect the presence of webshells.
5. Security audit : Conduct a security audit on the web server to check for security loopholes, such as file upload loopholes, command injection loopholes, etc. Attackers often exploit these vulnerabilities to upload webshells.
The above methods cannot fully guarantee the detection of all webshells. Therefore, it is recommended to deploy a security protection solution on the web server, conduct regular security scans and audits, and update software patches in a timely manner.
6. Do you know about JAVA memory horse checking?
Java memory horse, also known as Java remote code execution vulnerability, is an attack method that exploits Java deserialization vulnerabilities. An attacker can execute arbitrary code on the target server by constructing a malicious serialized object, sending it to the target server and triggering the deserialization operation.
The following are several methods for troubleshooting Java memory horses:
1. Tracking log files : If the system has been attacked, you should first check the system log files to find abnormal request or response content, and combine other information to determine whether there is a Java memory horse.
2. Check network traffic : You can use network capture tools such as Wireshark to monitor the network traffic of the server, analyze the data content in the message, and find out whether there is any abnormal Java serialization data.
3. Check for deserialization vulnerabilities : Java memory horses use Java deserialization vulnerabilities, so we can use some deserialization vulnerability scanning tools (such as ysoserial) to detect whether the system is affected by such vulnerabilities, and Fix bugs in time.
4. Check the system process : Java memory horse usually starts a new process on the target server to execute malicious code, so you can check the system process list to find out whether there are unclear or abnormal processes.
5. Install security software : In order to better ensure the security of the system, you can install some professional security software, such as anti-virus software, intrusion detection system (IDS), etc., and scan and audit regularly.
7. How should you analyze a relatively large log?
Processing efficiency can be improved by making rational use of computer hardware, such as using multi-core CPUs and high-speed disks. At the same time, tasks can also be decomposed into multiple small parts for parallel processing to further improve analysis efficiency.
The specific process is as follows:
1. Preprocess the log file : If the log file is relatively large, you can first considercutting and filtering it. (You can use the split command in the Linux system to split a large log file into multiple small files for subsequent processing.)
2. Determine the log format : Before analyzing the log, you need to know the format of the log, such as time stamp, event type, IP address and other information. This helps us quickly locate and analyze the contents of the logs.
3. Use tools for analysis : There are currently many software tools for log analysis on the market, such as ELK Stack, Splunk, etc. These tools can help us analyze, search and visualize log data more efficiently.
4. Define the analysis goal : Before starting to analyze the log, it is necessary to clarify the results to be obtained and the questions to be answered. For example, we may need to look for a specific event or behavior, identify security-related anomalies or potential threats, and so on.
5. Analyze and record conclusions : According to the analysis objectives, use corresponding methods and tools to analyze log files and record the analysis conclusions. At the same time, it is necessary to organize and summarize the abnormalities or useful information found.
6. Take corresponding measures : According to the analysis results, determine the measures that need to be taken. For example, fix vulnerabilities, update security policies, strengthen access controls, etc.
8. How to analyze the data flow that is proxied?
The proxied data flow is usually intercepted and forwarded by the proxy server, and the data flow can be analyzed with the help of proxy tools (such as Burp Suite ). Here are some possible analysis methods:
1. Intercept and replay requests : By intercepting requests, modifying them, and sending requests to the target server again, observe how the application responds to these requests.
2. View request and response header information : including cookies, UserAgent, etc.
3. Analyze the HTTP response body : The proxy tool can capture the HTTP response body, and can view the HTML, JavaScript, CSS, images, etc. returned by the application to understand the structure and behavior of the application.
4. Find sensitive information : Record and analyze all HTTP traffic, and search for sensitive information to find out whether sensitive information such as passwords and credentials have been leaked.
5. Use plug-ins for analysis : Proxy tools usually have various plug-ins, such as XSS scanners, SQL injection scanners, vulnerability scanners, etc., which can be used to detect vulnerabilities and security risks in applications.
9. After being attacked, how to check if the log files and Trojan files are deleted ?
1. Check the system backup : If your system has been backed up regularly, you can try to restore the lost log files and horse files from the backup. This can be very effective if the backup is not compromised.
2. Recover deleted files : some data recovery software, such as Recuva, EaseUS Data Recovery, etc.
3. Check other hosts : If your system is integrated into the network, you can check other hosts for the same attack signs and backdoor programs.
4. Analyze system snapshots : If your system supports system snapshot functions, such as Windows system restore points, you can try to roll back the system to the previous snapshot state, and analyze the log information and system status in this state to find the attack line. evidence for.
5. Log audit : If the log file is deleted, you can try to collect log information through other channels and conduct audit analysis. For example, information such as network traffic, system performance, and system processes can be checked to determine whether there is any abnormal behavior.
10. How to trace the source of traffic through the wireshark tool?
1. Open the Wireshark software and start capturing network traffic.
2. Filter out the data packets that need attention . For example, use the filter "ip.addr == [destination IP address]" in Wireshark to filter out relevant packets.
3. Find packets involving the destination IP address and analyze them. You can view the detailed information of the data packet, such as source IP address, destination IP address, port number, protocol type, etc., to obtain more information about the attacker.
4. According to the source IP address and port number of the data packet, determine the network or host where the attacker may be located . Additional information such as registrant name, email address, phone number, etc. can be found through a WHOIS lookup.
5. In-depth analysis of data packets to determine whether there is malicious activity. For example, check whether the files transmitted in the data packets are infected, or check whether there are abnormal traffic or frequent connection attempts, etc.
11. Several servers on the intranet, one of them was penetrated, how to troubleshoot?
After checking that a server has been attacked, it is necessary to take quick and targeted measures, and analyze and repair according to the specific situation, so as to protect the security of the system and sensitive data.
1. Preserve the scene : better understand the behavior of attackers, the propagation path of malicious code, and other systems or data that may be affected.
2. Collect evidence : such as intrusion detection logs, application logs, network traffic capture, etc. This evidence can help us determine the type of attack, when it occurred, and the tools and techniques used by the attackers.
3. Cut off the network connection : This can be achieved by unplugging the network cable, closing related ports, or disabling the network adapter.
4. Analyze malicious code : determine its behavior, mode of propagation, and degree of harm.
5. Verify system integrity : such as checking the hash value of system files, comparing configuration file differences, etc.
6. Vulnerability scanning : Vulnerability scanning of the entire intranet to ensure that other servers have not been attacked. Tools such as Nessus, OpenVAS, etc.
7. Strengthen security measures : such as updating patches, upgrading software, strengthening firewall rules, etc.