Rules of AEM

ERROR :-   OakAccess0000: Access denied We often observe while doing the AEM development or in live running environment we get the error code  OakAccess0000 , while running a workflow or any asset upload.  This impact the business as content author are unable to upload any content.  Error stack trace :- Javax.jcr.AccessDeniedException: OakAccess0000: Access denied  at org.apache.jackrabbit.oak.api.CommitFailedException.asRepositoryException(CommitFailedException.java:232) [org.apache.jackrabbit.oak-api:1.10.6]  at org.apache.jackrabbit.oak.api.CommitFailedException.asRepositoryException(CommitFailedException.java:213) [org.apache.jackrabbit.oak-api:1.10.6]  at org.apache.jackrabbit.oak.jcr.delegate.SessionDelegate.newRepositoryException(SessionDelegate.java:669) [org.apache.jackrabbit.oak-jcr:1.10.6]  at org.apache.jackrabbit.oak.jcr.delegate.SessionDelegate.save(SessionDelegate.java:495) [org.apache.jackrabbit.oak-jcr:1.10.6]  at org.apache.jackrabbit.oak.jcr.session.SessionImpl$8.per

Prevent Denial of Service (DoS) Attacks : AEM  A denial of service (DoS) attack is an attempt to make a computer resource unavailable to its intended users. You can get more information on DDoS prevention in Apache At the dispatcher level, there are two methods of configuring to prevent DoS attacks: Use the mod_rewrite module (for example,  Apache 2.4 ) to perform URL validations (if the URL pattern rules are not too complex). Prevent the dispatcher from caching URLs with spurious extensions by using  filters .  For example, change the caching rules to limit caching to the expected mime types, such as .html .jpeg .gif .swf .js .doc .pdf .ppt .... as per your project requirement. An example configuration file is given below,  for  this includes restrictions for mime types.      When configuring Dispatcher you should restrict external access as much as possible. The      following example provides example for the minimal access for external visitors, you can refer the default file.  /fi

 SSL handshake error while replication  While configuring the SSL between author and publish servers, for a secured data flow you want to make the replication calls also over HTTPS.  Assumption -      Author and publish servers will have working SSL and sling security check should be pass.  Error -   Replication test  failed PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target Cause -  This issue comes as replication agents try to find the certificates with exact name. and it ignores the wild card certificates.  Solution  -  Login to AEM , open replication agent which has the error. Edit the replication agent Go to transport  Make ssl to R elaxed . 

Prevent DDoS in Apache & IP Block Automation DDoS (Distributed Denial of Service) attacks are a type of cyberattack that can cause serious damage to your web server. These attacks involve flooding your server with a huge volume of traffic, overwhelming its resources and causing it to crash. In this blog post, we'll discuss how to prevent DDoS attacks in Apache, without using any third part tool/application.     Available Options to Prevent DDoS : You can use various mentioned methods to achieve the same. But using WAF, CDN, etc will cost extra dollars. Which might not be necessary for a small scale application.   Use a Web Application Firewall (WAF): A WAF can help detect and block malicious traffic before it reaches your Apache server. It can also help block common attack vectors, such as SQL injection and cross-site scripting (XSS). Install mod_evasive: mod_evasive is an Apache module that helps detect and block DDoS attacks. It wor

Crypto Support in AEM (Syncing HMAC among AEM instances) AEM OOTB provides a feature where we can encrypt the secured and confidential data through OOTB AEM Crypto Support and store it in a code repository in the form of OSGi configuration. Crypto Support is based on keys (hmac and master files) which are unique for each AEM instance. Encrypted text generated for the same plain-text string on one AEM instance will be different from another instance. This can raise alarms in cases where we have the same OSGi configuration values shared among Author and Publish instances under the same topology. For e.g. /apps/project/config.prod/com.day.cq.db.dbservice.xml Here DB password for Default DB Service will be same across all Prod AEM instances. So, in order to make sure that the same encrypted value works on all Prod instances, we will have to sync hmac and master files among Prod Author and Publish instances. Vital Points to know before HMAC SYNC  Sync of HMAC/keys will break the AEM SSL and