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Reposilite artifacts vulnerable to Stored Cross-site Scripting

High severity GitHub Reviewed Published Jun 16, 2024 in dzikoysk/reposilite • Updated Aug 2, 2024

Package

maven com.reposilite:reposilite-backend (Maven)

Affected versions

>= 3.3.0, < 3.5.12

Patched versions

3.5.12

Description

Summary

Reposilite v3.5.10 is affected by Stored Cross-Site Scripting (XSS) when displaying artifact's content in the browser.

Details

As a Maven repository manager, Reposilite provides the ability to view the artifacts content in the browser, as well as perform administrative tasks via API. The problem lies in the fact that the artifact's content is served via the same origin (protocol/host/port) as the Admin UI. If the artifact contains HTML content with javascript inside, the javascript is executed within the same origin. Therefore, if an authenticated user is viewing the artifacts content, the javascript inside can access the browser's local storage where the user's password (aka 'token-secret') is stored.
It is especially dangerous in scenarios where Reposilite is configured to mirror third party repositories, like the Maven Central Repository. Since anyone can publish an artifact to Maven Central under its own name, such malicious packages can be used to attack the Reposilite instance.

Steps to reproduce

To demonstrate this vulnerability, we can start Reposilite with default settings at localhost:8080 and configure its 'release' repository to mirror https://artsploit.com/maven. This is my own website intended to emulate http://repo1.maven.org/, but it also contains a proof-of-concept payload for this vulnerability. Technically I could publish this payload to Maven Central Repository, but I don't want to clutter it.

Then, as an administrator or authenticated Reposilite user, navigate to http://localhost:8080/releases/com/artsploit/reposilite-xss/1.0/reposilite-xss-1.0.pom in the browser.
This file contains the basic application/xml payload:

<?xml version="1.0" encoding="UTF-8"?>
<a:script xmlns:a="http://www.w3.org/1999/xhtml">
    alert(`Secret key: ${localStorage.getItem('token-secret')}`)
</a:script>

The script will be executed within the http://localhost:8080/ origin and the leaked token is displayed.

image

Impact

This issue may lead to the full Reposilite instance compromise. If this attack is performed against the admin user, it's possible to use the admin API to modify settings and artifacts on the instance. In the worst case scenario, an attacker would be able to obtain the Remote code execution on all systems that use artifacts from Reposilite.

It's important to note that the attacker does not need to lure a victim user to use a malicious artifact, but just open a link in the browser. This link can be silently loaded among the other HTML content, making this attack unnoticeable.

Even if the Reposilite instance is located in an isolated environment, such as behind a VPN or in the local network, this attack is still possible as it can be performed from the admin browser.

Remediation

When serving artifact's content via HTTPS, it's important to understand that this content might be potentially untrusted HTML code, so the javascript execution should be restricted.
Consider the following options to remediate this vulnerability:

  • [preferred] Use the "Content-Security-Policy: sandbox;" header when serving artifact's content. This makes the resource treated as being from a special origin that always fails the same-origin policy (potentially preventing access to data storage/cookies and some JavaScript APIs).
  • [not preferred, but also works] Use the "Content-Disposition: attachment" header. This will prevent the browser from displaying the content entirely, so it just saves it to the local filesystem.

Additionally, we strongly recommend reconsidering how the website authentication works for Reposilite. Storing user's passwords in plaintext in the browser's local storage is not an ideal option. The more robust and secure option would be to issue a one time session ID or a token to the browser after checking the login/password on the server. These session IDs or tokens should have limited validity time, so their compromise would be trickier to exploit.

References

@dzikoysk dzikoysk published to dzikoysk/reposilite Jun 16, 2024
Published to the GitHub Advisory Database Aug 2, 2024
Reviewed Aug 2, 2024
Last updated Aug 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 v4 base metrics

Exploitability Metrics
Attack Vector Network
Attack Complexity Low
Attack Requirements Present
Privileges Required None
User interaction Passive
Vulnerable System Impact Metrics
Confidentiality High
Integrity High
Availability High
Subsequent System Impact Metrics
Confidentiality None
Integrity None
Availability None

CVSS v4 base metrics

Exploitability Metrics
Attack Vector: This metric reflects the context by which vulnerability exploitation is possible. This metric value (and consequently the resulting severity) will be larger the more remote (logically, and physically) an attacker can be in order to exploit the vulnerable system. The assumption is that the number of potential attackers for a vulnerability that could be exploited from across a network is larger than the number of potential attackers that could exploit a vulnerability requiring physical access to a device, and therefore warrants a greater severity.
Attack Complexity: This metric captures measurable actions that must be taken by the attacker to actively evade or circumvent existing built-in security-enhancing conditions in order to obtain a working exploit. These are conditions whose primary purpose is to increase security and/or increase exploit engineering complexity. A vulnerability exploitable without a target-specific variable has a lower complexity than a vulnerability that would require non-trivial customization. This metric is meant to capture security mechanisms utilized by the vulnerable system.
Attack Requirements: This metric captures the prerequisite deployment and execution conditions or variables of the vulnerable system that enable the attack. These differ from security-enhancing techniques/technologies (ref Attack Complexity) as the primary purpose of these conditions is not to explicitly mitigate attacks, but rather, emerge naturally as a consequence of the deployment and execution of the vulnerable system.
Privileges Required: This metric describes the level of privileges an attacker must possess prior to successfully exploiting the vulnerability. The method by which the attacker obtains privileged credentials prior to the attack (e.g., free trial accounts), is outside the scope of this metric. Generally, self-service provisioned accounts do not constitute a privilege requirement if the attacker can grant themselves privileges as part of the attack.
User interaction: This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable system. This metric determines whether the vulnerability can be exploited solely at the will of the attacker, or whether a separate user (or user-initiated process) must participate in some manner.
Vulnerable System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the VULNERABLE SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the VULNERABLE SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the VULNERABLE SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
Subsequent System Impact Metrics
Confidentiality: This metric measures the impact to the confidentiality of the information managed by the SUBSEQUENT SYSTEM due to a successfully exploited vulnerability. Confidentiality refers to limiting information access and disclosure to only authorized users, as well as preventing access by, or disclosure to, unauthorized ones.
Integrity: This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. Integrity of the SUBSEQUENT SYSTEM is impacted when an attacker makes unauthorized modification of system data. Integrity is also impacted when a system user can repudiate critical actions taken in the context of the system (e.g. due to insufficient logging).
Availability: This metric measures the impact to the availability of the SUBSEQUENT SYSTEM resulting from a successfully exploited vulnerability. While the Confidentiality and Integrity impact metrics apply to the loss of confidentiality or integrity of data (e.g., information, files) used by the system, this metric refers to the loss of availability of the impacted system itself, such as a networked service (e.g., web, database, email). Since availability refers to the accessibility of information resources, attacks that consume network bandwidth, processor cycles, or disk space all impact the availability of a system.
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

EPSS score

0.045%
(17th percentile)

Weaknesses

CVE ID

CVE-2024-36115

GHSA ID

GHSA-9w8w-34vr-65j2

Source code

Credits

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