Server-Side Request Forgery (SSRF) in Karaf - CVE-2020-11980
Published: June 13, 2020 / Updated: July 17, 2020
Karaf
Detailed vulnerability description
The vulnerability allows a remote authenticated user to execute arbitrary code.
In Karaf, JMX authentication takes place using JAAS and authorization takes place using ACL files. By default, only an "admin" can actually invoke on an MBean. However there is a vulnerability there for someone who is not an admin, but has a "viewer" role. In the 'etc/jmx.acl.cfg', such as role can call get*. It's possible to authenticate as a viewer role + invokes on the MLet getMBeansFromURL method, which goes off to a remote server to fetch the desired MBean, which is then registered in Karaf. At this point the attack fails as "viewer" doesn't have the permission to invoke on the MBean. Still, it could act as a SSRF style attack and also it essentially allows a "viewer" role to pollute the MBean registry, which is a kind of privilege escalation. The vulnerability is low as it's possible to add a ACL to limit access. Users should update to Apache Karaf 4.2.9 or newer.