CVE-2024-27894 Apache Pulsar: Pulsar Functions Worker Allows Unauthorized File Access and Unauthorized HTTP/HTTPS Proxying

What is CVE-2024-27894?

CVE-2024-27894 is a high-severity server-side request forgery vulnerability in Apache Pulsar, published on 12 Mar 2024. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

The Pulsar Functions Worker includes a capability that permits authenticated users to create functions where the function's implementation is referenced by a URL. The supported URL schemes include "file", "http", and "https". When a function is created using this method, the Functions Worker will retrieve the implementation from the URL provided by the user. However, this feature introduces a vulnerability that can be exploited by an attacker to gain unauthorized access to any file that the Pulsar Functions Worker process has permissions to read. This includes reading the process environment which potentially includes sensitive information, such as secrets. Furthermore, an attacker could leverage this vulnerability to use the Pulsar Functions Worker as a proxy to access the content of remote HTTP and HTTPS endpoint URLs. This could also be used to carry out denial of service attacks. This vulnerability also applies to the Pulsar Broker when it is configured with "functionsWorkerEnabled=true".

This issue affects Apache Pulsar versions from 2.4.0 to 2.10.5, from 2.11.0 to 2.11.3, from 3.0.0 to 3.0.2, from 3.1.0 to 3.1.2, and 3.2.0.

2.10 Pulsar Function Worker users should upgrade to at least 2.10.6. 2.11 Pulsar Function Worker users should upgrade to at least 2.11.4. 3.0 Pulsar Function Worker users should upgrade to at least 3.0.3. 3.1 Pulsar Function Worker users should upgrade to at least 3.1.3. 3.2 Pulsar Function Worker users should upgrade to at least 3.2.1.

Users operating versions prior to those listed above should upgrade to the aforementioned patched versions or newer versions.

The updated versions of Pulsar Functions Worker will, by default, impose restrictions on the creation of functions using URLs. For users who rely on this functionality, the Function Worker configuration provides two configuration keys: "additionalEnabledConnectorUrlPatterns" and "additionalEnabledFunctionsUrlPatterns". These keys allow users to specify a set of URL patterns that are permitted, enabling the creation of functions using URLs that match the defined patterns. This approach ensures that the feature remains available to those who require it, while limiting the potential for unauthorized access and exploitation.

Weakness: CWE-552, CWE-20

Which versions are affected by CVE-2024-27894?

10 open source packages ship an affected version, including org.apache.pulsar:pulsar-functions-worker. It affects 1 product.

Products include Apache Pulsar.

How do I fix CVE-2024-27894?

Upgrade org.apache.pulsar:pulsar-functions-worker to a fixed version for your release line: 2.11.4, 2.10.6, 3.0.3 or 3.1.3.

Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.

Is CVE-2024-27894 being exploited?

There is no known exploitation of CVE-2024-27894 in the wild and no public exploit code.

Other vulnerabilities in Apache Pulsar

• CVE-2021-22160 Authentication with JWT allows use of “none”-algorithm Critical 9.8
• CVE-2023-30429 Apache Pulsar: Incorrect Authorization for Function Worker when using mTLS Authentication through Pulsar Proxy Critical 9.6
• CVE-2024-27135 Apache Pulsar: Improper Input Validation in Pulsar Function Worker allows Remote Code Execution High 8.5
• CVE-2024-27317 Apache Pulsar: Pulsar Functions Worker's Archive Extraction Vulnerability Allows Unauthorized File Modification High 8.4
• CVE-2022-34321 Apache Pulsar: Improper Authentication for Pulsar Proxy Statistics Endpoint High 8.2

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-c2x9-vw5h-39vc.