There is a kind of brute-force trials to access Solr using a different PORT every few minutes

we are using Solr 7.2.1 with Sitecore 9.1 in the Azure app serves 

and we are notes in the log file error "

java.io.IOException: The user name or password is incorrect "

admin team restarted the Solr server and we noticed after restarting 

alot of requests and each request is followed by number of trials and it ends-up by exception firing.

There is a kind of brute-force trials to access a different PORT every few minutes) which all lead to failures

 

 

:java.io.IOException: The user name or password is incorrect

               at java.io.WinNTFileSystem.canonicalize0(Native Method)

               at java.io.WinNTFileSystem.canonicalize(WinNTFileSystem.java:428)

               at java.io.File.getCanonicalPath(File.java:620)

               at org.apache.solr.core.StandardDirectoryFactory.normalize(StandardDirectoryFactory.java:83)

               at org.apache.solr.core.CachingDirectoryFactory.get(CachingDirectoryFactory.java:334)

               at org.apache.solr.core.SolrCore.getNewIndexDir(SolrCore.java:351)

               at org.apache.solr.core.SolrCore.openNewSearcher(SolrCore.java:1977)

               at org.apache.solr.core.SolrCore.getSearcher(SolrCore.java:2215)

               at org.apache.solr.core.SolrCore.getSearcher(SolrCore.java:1952)

               at org.apache.solr.update.DirectUpdateHandler2.commit(DirectUpdateHandler2.java:715)

               at org.apache.solr.update.processor.RunUpdateProcessor.processCommit(RunUpdateProcessorFactory.java:93)

               at org.apache.solr.update.processor.UpdateRequestProcessor.processCommit(UpdateRequestProcessor.java:68)

               at org.apache.solr.update.processor.DistributedUpdateProcessor.doLocalCommit(DistributedUpdateProcessor.java:1882)

               at org.apache.solr.update.processor.DistributedUpdateProcessor.processCommit(DistributedUpdateProcessor.java:1858)

               at org.apache.solr.update.processor.LogUpdateProcessorFactory$LogUpdateProcessor.processCommit(LogUpdateProcessorFactory.java:160)

               at org.apache.solr.handler.loader.XMLLoader.processUpdate(XMLLoader.java:281)

               at org.apache.solr.handler.loader.XMLLoader.load(XMLLoader.java:188)

               at org.apache.solr.handler.UpdateRequestHandler$1.load(UpdateRequestHandler.java:97)

               at org.apache.solr.handler.ContentStreamHandlerBase.handleRequestBody(ContentStreamHandlerBase.java:68)

               at org.apache.solr.handler.RequestHandlerBase.handleRequest(RequestHandlerBase.java:177)

               at org.apache.solr.core.SolrCore.execute(SolrCore.java:2503)

               at org.apache.solr.servlet.HttpSolrCall.execute(HttpSolrCall.java:710)

               at org.apache.solr.servlet.HttpSolrCall.call(HttpSolrCall.java:516)

               at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:382)

               at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:326)

               at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1751)

               at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:582)

               at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)

               at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548)

               at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:226)

               at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1180)

               at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:512)

               at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:185)

               at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1112)

               at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)

               at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:213)

               at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:119)

               at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:134)

               at org.eclipse.jetty.rewrite.handler.RewriteHandler.handle(RewriteHandler.java:335)

               at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:134)

               at org.eclipse.jetty.server.Server.handle(Server.java:534)

               at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:320)

               at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:251)

               at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:283)

               at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:108)

               at org.eclipse.jetty.io.SelectChannelEndPoint$2.run(SelectChannelEndPoint.java:93)

               at org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.executeProduceConsume(ExecuteProduceConsume.java:303)

               at org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.produceConsume(ExecuteProduceConsume.java:148)

               at org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.run(ExecuteProduceConsume.java:136)

               at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:671)

               at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:589)

               at java.lang.Thread.run(Thread.java:748)

 

After restarting Server

we need to know the root cause of the issue and if this is some kind of attacks