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Apache Pulsar: Pulsar Functions Worker Allows Unauthorized File Access and Unauthorized HTTP/HTTPS Proxying

High severity GitHub Reviewed Published Mar 12, 2024 to the GitHub Advisory Database • Updated May 2, 2024

Package

maven org.apache.pulsar:pulsar-functions-worker (Maven)

Affected versions

>= 2.4.0, < 2.10.6
>= 2.11.0, < 2.11.4
>= 3.0.0, < 3.0.3
>= 3.1.0, < 3.1.3
>= 3.2.0, < 3.2.1

Patched versions

2.10.6
2.11.4
3.0.3
3.1.3
3.2.1

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.

References

Published by the National Vulnerability Database Mar 12, 2024
Published to the GitHub Advisory Database Mar 12, 2024
Reviewed Mar 14, 2024
Last updated May 2, 2024

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

EPSS score

0.045%
(16th percentile)

Weaknesses

CVE ID

CVE-2024-27894

GHSA ID

GHSA-c2x9-vw5h-39vc

Source code

Credits

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