F5 ASM XML processing - policy name.
Hello, we have an error message in logs: ASM out of memory error: event code X89 Exceeded maximum memory assigned for XML processing we have already increased both variables total_xml_memory and additional_xml_memory_in_mb to 4GB but they still appear. What i wanted to ask if its possible to identify which ASM policy generates these logs? Or which policy is responsible for the most of xml memory usage? Is it possible to create an irule that will check this and assign custom violation with policy name (and request details) that raised this violation regarding xml memory? Because as it is now we would have to further increase additional xml memory variable and maybe its better to troubleshoot why is it getting exceeded in the first place?
Configuration of Pools VS LTM Policies and AWAF for Multiple Applications on Same Backend
I need your assistance and confirmation regarding a critical deployment involving F5 AWAF for internal applications. We have six internal applications accessible through the following URLs:https://gtt.XXX.ma:8443/gtt/;https://po.XXX.gov.ma:8443/po/;https://rpe.XXX.gov.ma/RPE/ https://sos.XXX.gov.ma/sos/;https://ant.XXX.gov.ma/ANT/;https://testcad.XXX.ma/testcad/. All these applications point to the same backend server at IP address 192.168.100.30. The DNS records for all of them resolve to the same IP address: 192.168.221.30. We are planning to configure two Virtual Servers using the same virtual IP address 192.168.200.20: One VS for applications running on port 443 ;One VS for applications running on port 8443: Each VS will have a dedicated LTM policy: One policy for the applications on port 443. Another policy for the applications on port 8443 . ach application must have its own dedicated AWAF (ASM) policy. Could you please confirm if this configuration is valid and supported by F5? Also we would like your recommendation on the following points: Should we configure a shared pool for all applications or a separate pool for each one?. Is the dual VS approach (with same IP but different ports) acceptable?. Is it the right approach to use LTM policies for routing requests and applying specific ASM policies per application? This deployment is critical and currently in preparation for production.Trigger js challenge/Captcha for ip reputation/ip intelligence categories
Problem solved by this Code Snippet Because some ISP or cloud providers do not monitor their users a lot of times client ip addresses are marked as "spam sources" or "windows exploits" and as the ip addresses are dynamic and after time a legitimate user can use this ip addresses the categories are often stopped in the IP intelligence profile or under the ASM/AWAF policy. This usually happens in Public Clouds that do not monitor what their users do and the IP gets marked as bad then another good user after a day or two has this ip address and this causes the issue. For many of my clients I had to stop the ip reputation/ip intelligence category "spam sources" and in some cases "windows exploits" so having a javascript/captcha checks seems a nice compromise 😎 To still make use of this categories the users coming from those ip addresses can be forced to solve captcha checks or at least to be checked for javascript support! How to use this Code Snippet Have AWAF/ASM and ip intelligence licensed Add AWAF/ASM policy with irule support option (by default not enabled under the policy) or/and Bot profile under the Virtual server Optionally add IP intelligence profile or enable the Ip intelligence under the WAF policy without the categories that cause a lot of false positives, Add the irule and if needed modify the categories for which it triggers Do not forget to first create the data group, used in the code or delete that part of the code and to uncomment the Bot part of the code, if you plan to do js check and not captcha and maybe comment the captcha part ! Code Snippet Meta Information Version: 17.1.3 Coding Language: TCL Code You can find the code and further documentation in my GitHub repository: reputation-javascript-captcha-challlenge/ at main · Nikoolayy1/reputation-javascript-captcha-challlenge when HTTP_REQUEST { # Take the ip address for ip reputation/intelligence check from the XFF header if it comes from the whitelisted source ip addresses in data group "client_ip_class" if { [HTTP::header exists "X-Forwarded-For"] && [class match [IP::client_addr] equals "/Common/client_ip_class"] } { set trueIP [HTTP::header "X-Forwarded-For"] } else { set trueIP [IP::client_addr] } # Check if IP reputation is triggered and it is containing "Spam Sources" if { ([llength [IP::reputation $trueIP]] != 0) && ([IP::reputation $trueIP] contains "Spam Sources") }{ log local0. "The category is [IP::reputation $trueIP] from [IP::client_addr]" # Set the variable 1 or bulean true as to trigger ASM captcha or bot defense javascript set js_ch 1 } else { set js_ch 0 } # Custom response page just for testing if there is no real backend origin server for testing if {!$js_ch} { HTTP::respond 200 content { <html> <head> <title>Apology Page</title> </head> <body> We are sorry, but the site you are looking for is temporarily out of service<br> If you feel you have reached this page in error, please try again. </body> </html> } } } # when BOTDEFENSE_ACTION { # Trigger bot defense action javascript check for Spam Sources # if {$js_ch && (not ([BOTDEFENSE::reason] starts_with "passed browser challenge")) && ([BOTDEFENSE::action] eq "allow") }{ # BOTDEFENSE::action browser_challenge # } # } when ASM_REQUEST_DONE { # Trigger ASM captcha check only for users comming from Spam sources that have not already passed the captcha check (don't have the captcha cookie) if {$js_ch && [ASM::captcha_status] ne "correct"} { set res [ASM::captcha] if {$res ne "ok"} { log local0. "Cannot send captcha_challenge: \"$res\"" } } } Extra References: BOTDEFENSE::action ASM::captcha ASM::captcha_status
'F5 rules for AWS WAF' ruleset not working for jsp web shell attack
I have subscribed to 'F5 rules for AWS WAF' Common Vulnerabilities & Exposures (CVE) Rules in AWS market place and protected the ALB's. Even after enabled, I see my web server got affected by jsp web shell attack and found war file deployed by unauthorized user. Can you please let me know what are the rules available to protect from jsp web shell attack?Mitigating OWASP 2019 API Security Top 10 risks using F5 NGINX App Protect
This 2019 API Security article provides a valuable summary of the OWASP API Security Top 10 risks identified for that year, outlining key vulnerabilities. We will deep-dive into some of those common risks and how we can protect our applications against these vulnerabilities using F5 NGINX App Protect. API2:2019 - Broken User Authentication Problem Statement: A critical API security risk, Broken Authentication occurs when weaknesses in the API's identity verification process permit attackers to circumvent authentication mechanisms. Successful exploitation leads attackers to impersonate legitimate users, gain unauthorized access to sensitive data, perform actions on behalf of victims, and potentially take over accounts or systems. This demonstration utilizes the Damn Vulnerable Web Application (DVWA) to illustrate the exploitability of Broken Authentication. We will execute a brute-force attack against the login interface, iterating through potential credential pairs to achieve unauthorized authentication. Below is the selenium automated script to execute brute-force attack, submitting multiple credential combinations to attempt authentication. The brute-force attack successfully compromised the authentication controls by iterating through multiple credential pairs, ultimately granting access. Solution: To mitigate the above vulnerability, NGINX App Protect is deployed and configured as reverse proxy in front of the application and requests are first validated by NAP for the vulnerabilities. The NGINX App Protect Brute Force WAF policy is utilized as shown below. Re-attempt to gain access to the application using the brute force approach is rejected and blocked. Support ID verification in the Security logs shows request is blocked because of Brute Force Policy. Request captured in NGINX App Protect security log API3:2019 - Excessive Data Exposure Problem Statement: As shown below in one of the demo application API’s, Personal Identifiable Information (PII) data, like Credit Card Numbers (CCN) and U.S. Social Security Numbers (SSN), are visible in responses that are highly sensitive. So, we must hide these details to prevent personal data exploits. Solution: To prevent this vulnerability, we will use the DataGuard feature in NGINX App Protect, which validates all response data for sensitive details and will either mask the data or block those requests, as per the configured settings. First, we will configure DataGuard to mask the PII data as shown below and will apply this configuration. Next, if we resend the same request, we can see that the CCN/SSN numbers are masked, thereby preventing data breaches. If needed, we can update configurations to block this vulnerability after which all incoming requests for this endpoint will be blocked. If you open the security log and filter with this support ID, we can see that the request is either blocked or PII data is masked, as per the DataGuard configuration applied in the above section. Request captured in NGINX App Protect security log API4:2019 - Lack of Resources & Rate Limiting Problem Statement: APIs do not have any restrictions on the size or number of resources that can be requested by the end user. Above mentioned scenarios sometimes lead to poor API server performance, Denial of Service (DoS), and brute force attacks. Solution: NGINX App Protect provides different ways to rate limit the requests as per user requirements. A simple rate limiting use case configuration is able to block requests after reaching the limit, which is demonstrated below. API6:2019 - Mass Assignment Problem Statement: API Mass Assignment vulnerability arises when clients can modify immutable internal object properties via crafted requests, bypassing API Endpoint restrictions. Attackers exploit this by sending malicious HTTP requests to escalate privileges, bypass security mechanisms, or manipulate the API Endpoint's functionality. Placing an order with quantity as 1: Bypassing API Endpoint restrictions and placing the order with quantity as -1 is also successful. Solution: To overcome this vulnerability, we will use the WAF API Security Policy in NGINX App Protect which validates all the API Security event triggered and based on the enforcement mode set in the validation rules, the request will either get reported or blocked, as shown below. Restricted/updated swagger file with .json extension is added as below: Policy used: App Protect API Security Re-attempting to place the order with quantity as -1 is getting blocked. Validating the support ID in Security log as below: Request captured in NGINX App Protect security log API7:2019 - Security Misconfiguration Problem Statement: Security misconfiguration occurs when security best practices are neglected, leading to vulnerabilities like exposed debug logs, outdated security patches, improper CORS settings, unnecessary allowed HTTP methods, etc. To prevent this, systems must stay up to date with security patches, employ continuous hardening, ensure API communications use secure channels (TLS), etc. Example: Unnecessary HTTP methods/verbs represent a significant security misconfiguration under the OWASP API Top 10. APIs often expose a range of HTTP methods (such as PUT, DELETE, PATCH) that are not required for the application's functionality. These unused methods, if not properly disabled, can provide attackers with additional attack surfaces, increasing the risk of unauthorized access or unintended actions on the server. Properly limiting and configuring allowed HTTP methods is essential for reducing the potential impact of such security vulnerabilities. Let’s dive into a demo application which has exposed “PUT” method., this method is not required as per the design and attackers can make use of this insecure unintended method to modify the original content. Solution: NGINX App Protect makes it easy to block unnecessary or risky HTTP methods by letting you customize which methods are allowed. By easily configuring a policy to block unauthorized methods, like disabling the PUT method by setting "$action": "delete", you can reduce potential security risks and strengthen your API protection with minimal effort. As shown below the attack request is captured in security log which conveys the request was successfully blocked, because of “Illegal method” violation. Request captured in NGINX App Protect security log API8:2019 - Injection Problem Statement: Customer login pages without secure coding practices may have flaws. Intruders could use those flaws to exploit credential validation using different types of injections, like SQLi, command injections, etc. In our demo application, we have found an exploit which allows us to bypass credential validation using SQL injection (by using username as “' OR true --” and any password), thereby getting administrative access, as below: Solution: NGINX App Protect has a database of signatures that match this type of SQLi attacks. By configuring the WAF policy in blocking mode, NGINX App Protect can identify and block this attack, as shown below. App Protect WAF Policy If you check in the security log with this support ID, we can see that request is blocked because of SQL injection risk, as below. Request captured in NGINX App Protect security log API9:2019 - Improper Assets Management Problem Statement: Improper Asset Management in API security signifies the crucial risk stemming from an incomplete awareness and tracking of an organization's full API landscape, including all environments like development and staging, different versions, both internal and external endpoints, and undocumented or "shadow" APIs. This lack of comprehensive inventory leads to an expanded and often unprotected attack surface, as security measures cannot be consistently applied to unknown or unmanaged assets. Consequently, attackers can exploit these overlooked endpoints, potentially find older, less secure versions or access sensitive data inadvertently exposed in non-production environments, thereby undermining overall security posture because you simply cannot protect assets you don't know exist. We’re using a flask database application with multiple API endpoints for demonstration. As part of managing API assets, the “/v1/admin/users” endpoint in the demo Flask application has been identified as obsolete. The continued exposure of the deprecated “/v1/admin/users” endpoint constitutes an Improper Asset Management vulnerability, creating an unnecessary security exposure that could be leveraged for exploitation. <public_ip>/v1/admin/users The current endpoint for user listing is “/v2/users”. <public_ip>/v2/users with user as admin1 Solution: To mitigate the above vulnerability, we are using NGINX as an API Gateway. The API Gateway acts as a filtering gateway for API incoming traffic, controlling, securing, and routing requests before they reach the backend services. The server’s name used for the above case is “f1-api” which is listening to the public IP where our application is running. To query the “/v1/admin/users” endpoint, use the curl command as shown below. Below is the configuration for NGINX as API Gateway, in “api_gateway.conf”, where “/v1/admin/users” endpoint is deprecated. The “api_json_errors.conf” is configured with error responses as shown below and included in the above “api_gateway.conf”. Executing the curl command against the endpoint yields an “HTTP 301 Moved Permanently” response. https://f1-api/v1/admin/users is deprecated API10:2019 - Insufficient Logging & Monitoring Problem Statement: Appropriate logging and monitoring solutions play a pivotal role in identifying attacks and also in finding the root cause for any security issues. Without these solutions, applications are fully exposed to attackers and SecOps is completely blind to identifying details of users and resources being accessed. Solution: NGINX provides different options to track logging details of applications for end-to-end visibility of every request both from a security and performance perspective. Users can change configurations as per their requirements and can also configure different logging mechanisms with different levels. Check the links below for more details on logging: https://www.nginx.com/blog/logging-upstream-nginx-traffic-cdn77/ https://www.nginx.com/blog/modsecurity-logging-and-debugging/ https://www.nginx.com/blog/using-nginx-logging-for-application-performance-monitoring/ https://docs.nginx.com/nginx/admin-guide/monitoring/logging/ https://docs.nginx.com/nginx-app-protect-waf/logging-overview/logs-overview/ Conclusion: In short, this article covered some common API vulnerabilities and shows how NGINX App Protect can be used as a mitigation solution to prevent these OWASP API security risks. Related resources for more information or to get started: F5 NGINX App Protect OWASP API Security Top 10 2019 OWASP API Security Top 10 2023Mitigating OWASP Web Application Security Top 10 risks using F5 NGINX App Protect
The OWASP Web Application Security Top 10 outlines the most critical security risks to web applications, serving as a global standard for understanding and mitigating vulnerabilities. Based on data from over 500,000 real-world applications, the list highlights prevalent security issues. The 2021 edition introduces new categories such as "Insecure Design" and "Software and Data Integrity Failures" emphasizing secure design principles and proactive security throughout the software development lifecycle. For more information please visit: OWASP Web Application Security Top 10 - 2021 F5 products provide controls to secure applications against these risks. F5 NGINX App Protect offers security controls using both positive and negative security models to protect applications from OWASP Top 10 risks. The positive security model combines validated user sessions, user input, and application response, while the negative security model uses attack signatures to detect and block OWASP Top 10 application security threats. This guide outlines how to implement effective protection based on the specific needs of your application. Note - The OWASP Web Application Security Top 10 risks listed below are tested on both F5 NGINX App Protect versions 4.x and 5.x A01:2021-Broken Access Control Problem statement: As the risk name suggests, Broken Access Control refers to failures in access control mechanisms that lead to a vulnerable application. In this demonstration, the application is susceptible to “Directory/Path Traversal” via the URL, which allows unauthorized access to sensitive information stored on the server. Solution: F5 NGINX App Protect WAF(Web Application Firewall) offers an inherent solution to the “Directory/Path Traversal” vulnerability discussed, through its “app_protect_default_policy” bundle. This policy, which will be active by default when “App Protect” is enabled in the nginx configuration, helps prevent Directory/Path Traversal attacks by validating the values provided to the “page” key in URL. The attack request is recorded in the security log, indicating that the attack type is Predictable Resource Location, Path Traversal. The request was blocked, and the signatures responsible for detecting the attack are also visible. Note: The security log shown in the image below is not the default log configuration but has been customized by following the instructions provided in the link. A02:2021-Cryptographic Failures Problem statement: Earlier this attack was known as “Sensitive Data Exposure”, focusing on cryptographic failures that often result in the exposure of sensitive data. The “Juice Shop” demo application, as demonstrated below, is vulnerable to sensitive information disclosure due to the insecure storage of data, which is displayed in plain text to end users. Solution: F5 NGINX App Protect WAF provides best in class “Data Guard” policy, which can block as well as mask (based on policy configuration) sensitive information displayed to the end users. After applying the policy to mask the sensitive data, it’s observed the sensitive information which was visible(Fig. 2.1) is masked now. The attack request is recorded in the security log, indicating that the dataguard_mask policy is triggered, and the request was alerted. . 2.4 – Request captured in NGINX App Protect security log A03:2021-Injection Problem statement: An injection vulnerability arises when an application fails to properly handle user-supplied data, sending it to an interpreter (e.g., a database or operating system) as part of a query or command. Without proper validation, filtering, or sanitization, attackers can inject malicious code, leading to unauthorized access, data breaches, privilege escalation, or system compromise. For example, the DVWA demo application shown below lacks input validation, making it vulnerable to SQL injection attacks that can compromise confidential data. Solution: F5 NGINX App Protect WAF has a robust set of attack signatures which are pre-bundled in default policy. The SQL-Injection vulnerability discussed above can be prevented by enabling App Protect which has around 1000+ signatures related to variety of Injection attacks. The attack request is recorded in the security log, indicating that the attack type is SQL-Injection. The request was blocked, and the signatures responsible for detecting the attack are also visible. A04:2021-Insecure Design Problem statement: The growing reliance on web applications exposes them to security risks, with insecure design being a key concern. For example, a retail chain’s e-commerce website lacks protection against bots used by scalpers to buy high-end video cards in bulk for resale. This causes negative publicity and frustrates genuine customers. Implementing anti-bot measures and domain logic rules can help block fraudulent transactions, with F5 NGINX App Protect providing effective protection against such attacks. Solution: Secure design is an ongoing process that continuously evaluates threats, ensures robust code, and integrates threat modeling into development. It involves constant validation, accurate flow analysis, and thorough documentation. By using F5 NGINX App Protect WAF, which includes bot defense, web applications can effectively prevent bot-driven attacks, identifying and blocking them early to protect against fraudulent transactions. The attack request is recorded in the security log, indicating that the attack type is Non-browser Client. The request was blocked, and the violation stating “VIOL_BOT_CLIENT”. Note: The security log shown in the image below is the default log configuration Request captured in NGINX App Protect security log A05:2021-Security Misconfiguration Problem statement: Security misconfiguration occurs when security settings are improperly configured, exposing web applications to various threats. One such vulnerability is Cross-Site Request Forgery (CSRF), where attackers trick authenticated users into making unauthorized requests. Without proper protection mechanisms, attackers can exploit this misconfiguration to perform malicious actions on behalf of the user. The demonstration using WebGoat below shows how an improperly configured application becomes vulnerable to CSRF, allowing attackers to carry out unauthorized actions. Execute the above malicious script by copying the file path and pasting in new tab of the WebGoat authenticated browser. The script will automatically load the malicious code and redirects to the vulnerable page. Solution: F5 NGINX App Protect WAF provides a comprehensive support against CSRF attack. Users can configure the CSRF policy based on their requirements by following the configuration settings here. In this demonstration, default CSRF policy is used to block the attack. Default CSRF policy used to block CSRF attacks The security log captures the attack request, identifying the type of attack which is CSRF. The request was successfully blocked, and the violations saying “CSRF attack detected” is also visible. A06:2021-Vulnerable and Outdated Components Problem statement: Vulnerable and Outdated Components risk arises when a web application uses third-party libraries or software with known security vulnerabilities that are not updated. Additionally, vulnerable pages like “phpmyadmin.php” that expose sensitive details—such as application versions, user credentials, and database information—further increase the risk. Attackers can use this information to exploit known vulnerabilities or gain unauthorized access, leading to potential data breaches or system compromise. Solution: The vulnerability discussed above can be mitigated using F5 NGINX App Protect WAF Attack Signatures, which includes specific "Signature ID" for various vulnerabilities. These Signature IDs can be incorporated into the policy file to block attacks. For instance, Signature ID 200000014 can be used to block access to phpmyadmin.php page. Attack signatures can be found here. The attack request is recorded in the security log, indicating that the attack type is Predictable Resource Location. The request was blocked, and the signatures responsible for detecting the “/phpmyadmin/ page” attack are also visible. A07:2021-Identification and Authentication Failures Problem statement: Effective authentication and secure session management are crucial in preventing authentication-related vulnerabilities in daily tasks. Applications with weak authentication mechanisms are vulnerable to automated attacks, such as credential stuffing, where attackers use wordlists to perform spray attacks, allowing attackers to determine whether specific credentials are valid, thus increasing the risk of brute-force and other automated attacks. Brute force attacks are attempts to break in to secured areas of a web application by trying exhaustive, systematic, username/password combinations to discover legitimate authentication credentials. Solution: To prevent brute force attacks, F5 NGINX App Protect WAF monitors IP addresses, usernames, and the number of failed login attempts beyond a maximum threshold. When brute force patterns are detected, the F5 NGINX App Protect WAF policy either trigger an alarm or block the attack if the failed login attempts reached a maximum threshold for a specific username or coming from a specific IP address. Note – Brute force attack prevention is supported starting from versions v4.13 and v5.5 The security log captures the attack request, identifying the type of attack as Brute Force Attack. The request was successfully blocked, and the “VIOL_BRUTE_FORCE” violations is also visible. A08:2021-Software and Data Integrity Failures Problem statement: Added as a new entry in the OWASP Top 10 2021, software and data integrity failures, particularly in the context of insecure deserialization, occur when an application deserializes untrusted data without proper validation or security checks. This vulnerability allows attackers to modify or inject malicious data into the deserialization process, potentially leading to remote code execution, privilege escalation, or data manipulation. In this demonstration, a serialized PHP command O:18:"PHPObjectInjection":1:{s:6:"inject";s:18:"system ('ps -ef');";} is passed in the URL to retrieve the running processes. Solution: F5 NGINX App Protect WAF can prevent Serialization Injection PHP attacks by leveraging its default policy bundle, which includes an extensive set of signatures specifically designed to address deserialization vulnerabilities. The security log captures the attack request, identifying the type of attack. The request was successfully blocked, and the signatures used to detect the 'PHP Short Object Serialization Injection' attack are also visible. A09:2021-Security Logging and Monitoring Failures Problem statement: Security logging and monitoring failures occur when critical application activities such as logins, transactions, and user actions are not adequately logged or monitored. This lack of visibility makes it difficult to detect and respond to security breaches, attack attempts, or suspicious user behavior. Without proper logging and monitoring, attackers can exploit vulnerabilities without detection, potentially leading to data loss, revenue impact, or reputational damage. Insufficient logging also hinders the ability to escalate and mitigate security incidents effectively, making the application more vulnerable to exploitation. Solution: F5 NGINX App Protect WAF provides different options to track logging details of applications for end-to-end visibility of every request both from a security and performance perspective. Users can change configurations as per their requirements and can also configure different logging mechanisms with different levels. Check the links below for more details on logging: Version 4 and earlier Version 5 A10:2021-Server-Side Request Forgery Problem statement: Server-Side Request Forgery (SSRF) occurs when a web application fetches a remote resource without properly validating the user-supplied URL. This vulnerability allows attackers to manipulate the application into sending malicious requests to internal systems or external resources, bypassing security measures like firewalls or VPNs. SSRF attacks can expose sensitive internal data or resources that are not meant to be publicly accessible, making them a significant security risk, especially with modern cloud architectures. In this demonstration, patient health records, which should be accessible only within the network, can be retrieved publicly through SSRF. Solution: Server-Side Request Forgery (SSRF) attacks can be prevented by utilizing the default policy bundle of F5 NGINX App Protect WAF, which includes a comprehensive set of signatures designed to detect and mitigate SSRF vulnerabilities. By enabling App Protect, you gain strong defense against SSRF attacks as well as other prevalent security threats, thanks to the default policy's pre-configured signatures that cover a wide range of attack vectors. The security log captures the attack request, identifying the type of attack. The request was successfully blocked, and the signatures used to detect the 'SSRF' attack are also visible. Request captured in NGINX App Protect security log Conclusion: Protecting applications from attacks is simple with F5 NGINX App Protect WAF, a high-performance, lightweight, and platform-agnostic solution that supports diverse deployment options, from edge load balancers to Kubernetes clusters. By leveraging its advanced security controls, organizations can effectively mitigate the OWASP Web Application Security Top 10 risks, ensuring robust protection across distributed architectures and hybrid environments. Ultimately, F5 NGINX App Protect helps strengthen overall security, providing comprehensive defense for modern applications. References: F5 NGINX App Protect WAF OWASP Top 10 - 2021 F5 NGINX App Protect WAF Documentation F5 Attack Signatures
