I have just been working on an OSB SFTP business service, and got this error while testing the service.
While googling, I found out that you need to create a known_hosts file inside your OSB domain. The easiest way of creating a known_hosts file for me, was to use Cygwin and create a ssh (or sftp) connection to the destination.

Steps for the solution:

Cygwin: log in to remote system via ssh (or sftp)
Copy known_hosts file from ~/.ssh to OSB directory
Test business service

Cygwin: login to remote system

Use this command to login to the remote system:

ssh username@hostname

Optionally: Type ‘yes’ when asked if you trust this host
This will create an entry in your known_hosts file in the .ssh folder in your cygwin home directory
This is a (scrambled) contents of the known_hosts file:

joris@jorisworkstation/cygdrive/c/Oracle/Middleware/user_projects/domains/joris_domain/config/osb
$ cat ~/.ssh/known_hosts
10.200.242.65 ssh-rsa <<INSERT A LOT OF GARBLEGARBLE>>

Copy the known_hosts file to OSB

First we need to create the SFTP transports directory in the domain home:
Go to <<domain_home>>/config/osb and create this structure: (Only create the directories in RED)

- <<domain_home>>

- config

- osb

- transports

- sftp

We are now ready to copy the known_hosts file:
In cygwin:

 cp ~/.ssh/known_hosts /cygdrive/c/Oracle/Middleware/user_projects/domains/joris_domain/config/osb/transports/sftp

In Windows: Find known_hosts in your cygwin home folder (in my case: in C:\development\program\cygwin\home\joris.visscher\.ssh\known_hosts) and copy it to the newly created “sftp” folder in your domain home.

Test business service

All steps are now done, we can test the business service!

Additional information:

You will encounter the following error in your logs when this error occurs:
com.sshtools.j2ssh.transport.InvalidHostFileException

####<18-ott-2012 10.57.33 CEST> <Error> <SFTPTransport> <JORISWORKSTATION> <osb_server1> <[ACTIVE] ExecuteThread: '0' for queue: 'weblogic.kernel.Default (self-tuning)'> <<anonymous>> <> <cef9dbcf0859648a:31ba6f:13a730795ec:-8000-000000000000014f> <1350550653493> <BEA-381801> <Si ▒ verificato un errore per l'endpoint com.bea.wli.sb.transports.TransportException: com.sshtools.j2ssh.transport.InvalidHostFileException: Il file known_hosts non esiste o non dispone di autorizzazioni di lettura.
 com.bea.wli.sb.transports.TransportException: com.sshtools.j2ssh.transport.InvalidHostFileException: Il file known_hosts non esiste o non dispone di autorizzazioni di lettura.
 at com.bea.wli.sb.transports.sftp.connector.SFTPTransportProvider.sendMessage(SFTPTransportProvider.java:155)
 at com.bea.wli.sb.transports.sftp.connector.SFTPTransportProvider.sendMessageAsync(SFTPTransportProvider.java:110)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
 at java.lang.reflect.Method.invoke(Method.java:597)
 at com.bea.wli.sb.transports.Util$1.invoke(Util.java:83)
 at $Proxy122.sendMessageAsync(Unknown Source)
 at com.bea.wli.sb.transports.LoadBalanceFailoverListener.sendMessageAsync(LoadBalanceFailoverListener.java:148)
 at com.bea.wli.sb.transports.LoadBalanceFailoverListener.sendMessageToServiceAsync(LoadBalanceFailoverListener.java:603)
 at com.bea.wli.sb.transports.LoadBalanceFailoverListener.sendMessageToService(LoadBalanceFailoverListener.java:538)
 at com.bea.wli.sb.transports.TransportManagerImpl.sendMessageToService(TransportManagerImpl.java:566)
 at com.bea.wli.sb.transports.TransportManagerImpl.sendMessageAsync(TransportManagerImpl.java:434)
 at com.bea.wli.sb.test.service.ServiceMessageSender.send0(ServiceMessageSender.java:380)
 at com.bea.wli.sb.test.service.ServiceMessageSender.access$000(ServiceMessageSender.java:79)
 at com.bea.wli.sb.test.service.ServiceMessageSender$1.run(ServiceMessageSender.java:137)
 at com.bea.wli.sb.test.service.ServiceMessageSender$1.run(ServiceMessageSender.java:135)
 at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:363)
 at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:146)
 at com.bea.wli.sb.security.WLSSecurityContextService.runAs(WLSSecurityContextService.java:55)
 at com.bea.wli.sb.test.service.ServiceMessageSender.send(ServiceMessageSender.java:140)
 at com.bea.wli.sb.test.service.ServiceProcessor.invoke(ServiceProcessor.java:454)
 at com.bea.wli.sb.test.TestServiceImpl.invoke(TestServiceImpl.java:172)
 at com.bea.wli.sb.test.client.ejb.TestServiceEJBBean.invoke(TestServiceEJBBean.java:167)
 at com.bea.wli.sb.test.client.ejb.TestService_sqr59p_EOImpl.__WL_invoke(Unknown Source)
 at weblogic.ejb.container.internal.SessionRemoteMethodInvoker.invoke(SessionRemoteMethodInvoker.java:40)
 at com.bea.wli.sb.test.client.ejb.TestService_sqr59p_EOImpl.invoke(Unknown Source)
 at com.bea.wli.sb.test.client.ejb.TestService_sqr59p_EOImpl_WLSkel.invoke(Unknown Source)
 at weblogic.rmi.internal.BasicServerRef.invoke(BasicServerRef.java:667)
 at weblogic.rmi.cluster.ClusterableServerRef.invoke(ClusterableServerRef.java:230)
 at weblogic.rmi.internal.BasicServerRef$1.run(BasicServerRef.java:522)
 at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:363)
 at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:146)
 at weblogic.rmi.internal.BasicServerRef.handleRequest(BasicServerRef.java:518)
 at weblogic.rmi.internal.wls.WLSExecuteRequest.run(WLSExecuteRequest.java:118)
 at weblogic.work.ExecuteThread.execute(ExecuteThread.java:252)
 at weblogic.work.ExecuteThread.run(ExecuteThread.java:221)
 Caused By: com.sshtools.j2ssh.transport.InvalidHostFileException: Il file known_hosts non esiste o non dispone di autorizzazioni di lettura.
at com.bea.wli.sb.transports.sftp.client.KnownHostVerifier.validateKnownHosts(KnownHostVerifier.java:144)
at com.bea.wli.sb.transports.sftp.client.SFTPClient.authenticate(SFTPClient.java:108)
 at com.bea.wli.sb.transports.sftp.connector.SFTPResource.<init>(SFTPResource.java:78)
 at com.bea.wli.sb.transports.sftp.resource.SFTPUtils.createSFTPResource(SFTPUtils.java:170)
 at com.bea.wli.sb.transports.sftp.resource.SFTPConnectionPool.getResource(SFTPConnectionPool.java:104)
 at com.bea.wli.sb.transports.sftp.connector.SFTPTransportProvider.getSFTPResource(SFTPTransportProvider.java:958)
 at com.bea.wli.sb.transports.sftp.connector.SFTPTransportProvider.sendMessage(SFTPTransportProvider.java:145)
 at com.bea.wli.sb.transports.sftp.connector.SFTPTransportProvider.sendMessageAsync(SFTPTransportProvider.java:110)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
 at java.lang.reflect.Method.invoke(Method.java:597)
 at com.bea.wli.sb.transports.Util$1.invoke(Util.java:83)
 at $Proxy122.sendMessageAsync(Unknown Source)
 at com.bea.wli.sb.transports.LoadBalanceFailoverListener.sendMessageAsync(LoadBalanceFailoverListener.java:148)
 at com.bea.wli.sb.transports.LoadBalanceFailoverListener.sendMessageToServiceAsync(LoadBalanceFailoverListener.java:603)
 at com.bea.wli.sb.transports.LoadBalanceFailoverListener.sendMessageToService(LoadBalanceFailoverListener.java:538)
 at com.bea.wli.sb.transports.TransportManagerImpl.sendMessageToService(TransportManagerImpl.java:566)
 at com.bea.wli.sb.transports.TransportManagerImpl.sendMessageAsync(TransportManagerImpl.java:434)
 at com.bea.wli.sb.test.service.ServiceMessageSender.send0(ServiceMessageSender.java:380)
 at com.bea.wli.sb.test.service.ServiceMessageSender.access$000(ServiceMessageSender.java:79)
 at com.bea.wli.sb.test.service.ServiceMessageSender$1.run(ServiceMessageSender.java:137)
 at com.bea.wli.sb.test.service.ServiceMessageSender$1.run(ServiceMessageSender.java:135)
 at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:363)
 at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:146)
 at com.bea.wli.sb.security.WLSSecurityContextService.runAs(WLSSecurityContextService.java:55)
 at com.bea.wli.sb.test.service.ServiceMessageSender.send(ServiceMessageSender.java:140)
 at com.bea.wli.sb.test.service.ServiceProcessor.invoke(ServiceProcessor.java:454)
 at com.bea.wli.sb.test.TestServiceImpl.invoke(TestServiceImpl.java:172)
 at com.bea.wli.sb.test.client.ejb.TestServiceEJBBean.invoke(TestServiceEJBBean.java:167)
 at com.bea.wli.sb.test.client.ejb.TestService_sqr59p_EOImpl.__WL_invoke(Unknown Source)
 at weblogic.ejb.container.internal.SessionRemoteMethodInvoker.invoke(SessionRemoteMethodInvoker.java:40)
 at com.bea.wli.sb.test.client.ejb.TestService_sqr59p_EOImpl.invoke(Unknown Source)
 at com.bea.wli.sb.test.client.ejb.TestService_sqr59p_EOImpl_WLSkel.invoke(Unknown Source)
 at weblogic.rmi.internal.BasicServerRef.invoke(BasicServerRef.java:667)
 at weblogic.rmi.cluster.ClusterableServerRef.invoke(ClusterableServerRef.java:230)
 at weblogic.rmi.internal.BasicServerRef$1.run(BasicServerRef.java:522)
 at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:363)
 at weblogic.security.service.SecurityManager.runAs(SecurityManager.java:146)
 at weblogic.rmi.internal.BasicServerRef.handleRequest(BasicServerRef.java:518)
 at weblogic.rmi.internal.wls.WLSExecuteRequest.run(WLSExecuteRequest.java:118)
 at weblogic.work.ExecuteThread.execute(ExecuteThread.java:252)
 at weblogic.work.ExecuteThread.run(ExecuteThread.java:221)

Tag: Cygwin

Oracle Service Bus SFTP: BEA-381801 InvalidHostFileException

Steps for the solution:

Cygwin: login to remote system

Copy the known_hosts file to OSB

Test business service

Additional information: