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Path traversal in Reposilite javadoc file expansion (arbitrary file creation/overwrite) (`GHSL-2024-073`)

High severity GitHub Reviewed Published Jun 17, 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 an Arbitrary File Upload vulnerability via path traversal in expanding of Javadoc archives.

Details

Reposilite provides support for JavaDocs files, which are archives that contain documentation for artifacts. Specifically, JavadocEndpoints.kt controller allows to expand the javadoc archive into the server's file system and return its content. The problem is in the way how the archives are expanded, specifically how the new filename is created:

JavadocContainerService.kt#L127-L136

jarFile.entries().asSequence().forEach { file ->
    if (file.isDirectory) {
        return@forEach
    }

     val path = Paths.get(javadocUnpackPath.toString() + "/" + file.name)

    path.parent?.also { parent -> Files.createDirectories(parent) }
    jarFile.getInputStream(file).copyToAndClose(path.outputStream())
}.asSuccess<Unit, ErrorResponse>()

The file.name taken from the archive can contain path traversal characters, such as '/../../../anything.txt', so the resulting extraction path can be outside the target directory.

Impact

If the archive is taken from an untrusted source, such as Maven Central or JitPack for example, an attacker can craft a special archive to overwrite any local file on Reposilite instance. This could lead to remote code execution, for example by placing a new plugin into the '$workspace$/plugins' directory. Alternatively, an attacker can overwrite the content of any other package.

Note that the attacker can use its own malicious package from Maven Central to overwrite any other package on Reposilite.

Steps to reproduce

  1. Create a malicious javadoc archive that contains filenames with path traversal characters:
zip test-1.0-javadoc.jar ../../../../../../../../tmp/evil.txt index.html

Make sure that ../../../../../../../../tmp/evil.txt and index.html files exist on the system where you create this archive.

  1. Publish this archive to the repository which Reposilite is mirroring, such as Maven Central or JitPack. For the test purposes, I used my own server that imitates the upstream maven repository:
    http://artsploit.com/maven/com/artsploit/reposilite-zipslip/1.0/reposilite-zipslip-1.0-javadoc.jar

  2. Start Reposilite with 'releases' repository mirroring to 'http://artsploit.com/maven/'

  3. Now, if the attacker send the request to http://localhost:8080/javadoc/releases/com/artsploit/reposilite-zipslip/1.0, the aforementioned archive will be obtained from the http://artsploit.com/maven/com/artsploit/reposilite-zipslip/1.0/reposilite-zipslip-1.0-javadoc.jar address and its 'evil.txt' file will be expanded to '$workspace$/tmp/evil.txt'. Note that to perform this action, an attacker does not need to provide any credentials, as fetching from the mirrored repository does not require authentication.

  4. Confirm that '$workspace$/tmp/evil.txt' is created on the server where Reposilite is running.

Remediation

Normalize (remove all occurrences of /../) the file.name variable before concatenating it with javadocUnpackPath. E.g.:

val path = Paths.get(javadocUnpackPath.toString() + "/" + Paths.get(file.name).normalize().toString())

References

@dzikoysk dzikoysk published to dzikoysk/reposilite Jun 17, 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 None
Privileges Required Low
User interaction None
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:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

EPSS score

0.045%
(17th percentile)

Weaknesses

CVE ID

CVE-2024-36116

GHSA ID

GHSA-frvj-cfq4-3228

Source code

Credits

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