CVE-2020-11980
Description
From CVE.org
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.
Mitigation
It's possible to add a JMX ACL in etc configuration to limit access.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 8.8 | 6.3 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | High | Low | N/A |
| Integrity Impact | High | Low | N/A |
| Availability Impact | High | Low | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Application Data
Integrity
Technical Impact: Execute Unauthorized Code or Commands
Access Control
Technical Impact: Bypass Protection Mechanism
By providing URLs to unexpected hosts or ports, attackers can make it appear that the server is sending the request, possibly bypassing access controls such as firewalls that prevent the attackers from accessing the URLs directly. The server can be used as a proxy to conduct port scanning of hosts in internal networks, use other URLs such as that can access documents on the system (using file://), or use other protocols such as gopher:// or tftp://, which may provide greater control over the contents of requests.
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