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mindsdb arbitrary file write when extracting a remotely retrieved Tarball

High severity GitHub Reviewed Published Mar 30, 2023 in mindsdb/mindsdb • Updated Sep 25, 2024

Package

pip mindsdb (pip)

Affected versions

< 23.2.1.0

Patched versions

23.2.1.0

Description

Summary

An unsafe extraction is being performed using tarfile.extractall() from a remotely retrieved tarball. Which may lead to the writing of the extracted files to an unintended location. Sometimes, the vulnerability is called a TarSlip or a ZipSlip variant.

Details

I commented the following snippet of code as a vulnerability details. The code is from file.py#L26..L134

@ns_conf.route('/<name>')
@ns_conf.param('name', "MindsDB's name for file")
class File(Resource):
    @ns_conf.doc('put_file')
    def put(self, name: str):
        ''' add new file
            params in FormData:
                - file
                - original_file_name [optional]
        '''

        data = {}

        ... omitted for brevity

            url = data['source']
            data['file'] = data['name']

            ... omitted for brevity 

            with requests.get(url, stream=True) as r:                   # Source: retrieve the URL which point to a remotely located tarball 
                if r.status_code != 200:
                    return http_error(
                        400,
                        "Error getting file",
                        f"Got status code: {r.status_code}"
                    )
                file_path = os.path.join(temp_dir_path, data['file'])
                with open(file_path, 'wb') as f:
                    for chunk in r.iter_content(chunk_size=8192):   # write with chunks the remote retrieved file into file_path location 
                        f.write(chunk)

        original_file_name = data.get('original_file_name')

        file_path = os.path.join(temp_dir_path, data['file'])      
        lp = file_path.lower()
        if lp.endswith(('.zip', '.tar.gz')):
            if lp.endswith('.zip'):
                with zipfile.ZipFile(file_path) as f:
                    f.extractall(temp_dir_path)
            elif lp.endswith('.tar.gz'):
                with tarfile.open(file_path) as f:  # Just after 
                    f.extractall(temp_dir_path)  # Sink: the tarball located by file_path is supposed to be extracted to temp_dir_path.

So, a remotely available tarball is being retrieved and written to the server filesystem in chunks, and then, if the extension ends with .tar.gz of a compressed tarball, the mindsdb app applies tarfile.extractall() directly with no checks for the destination.

However, according to the following warning from the official documentation;

Warning: Never extract archives from untrusted sources without prior inspection. It is possible that files are created outside of path, e.g. members that have absolute filenames starting with "/" or filenames with two dots "..".

PoC

The following PoC is provided for illustration purposes only. It showcases the risk of extracting a non-harmless text file sim4n6.txt to one of the parent locations rather than the intended current folder.

> tar --list -v -f archive.tar.gz
tar: Removing leading "../../../" from member names
../../../sim4n6.txt

> python3 
Python 3.10.6 (main, Nov  2 2022, 18:53:38) [GCC 11.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import tarfile
>>> with tarfile.open("archive.tar.gz") as tf:
>>>         tf.extractall()
>>> exit()

> test -f ../../../sim4n6.txt && echo "sim4n6.txt exists"
sim4n6.txt exists

Attack Scenario

An attacker could craft a malicious tarball with a filename path, such as ../../../../../../../../etc/passwd, and then serve the archive remotely, proceed to the PUT request of the tarball through mindsdb and overwrite the system files of the hosting server for instance.

Mitigation

Potential mitigation could be to:

  • Use a safer module, like zipfile.
  • Use an alternative of tarfile, such as tarsafe.
  • Validate the location or the absolute path of the extracted files and discard those with malicious paths such as relative path ../../.. or absolute path such as /etc/password. A simple wrapper could be written to raise an exception when a path traversal may be identified.

This is similar to the other report GHSA-7x45-phmr-9wqp.

References

@ZoranPandovski ZoranPandovski published to mindsdb/mindsdb Mar 30, 2023
Published to the GitHub Advisory Database Mar 30, 2023
Reviewed Mar 30, 2023
Published by the National Vulnerability Database Apr 21, 2023
Last updated Sep 25, 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 None
User interaction None
Vulnerable System Impact Metrics
Confidentiality None
Integrity High
Availability None
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:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

EPSS score

0.146%
(52nd percentile)

Weaknesses

CVE ID

CVE-2023-30620

GHSA ID

GHSA-2g5w-29q9-w6hx

Source code

Credits

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