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Cache file, containing spotify auth token, is created with overly broad permissions

High
stephanebruckert published GHSA-pwhh-q4h6-w599 Feb 27, 2025

Package

pip spotipy (pip)

Affected versions

<= 2.25.0

Patched versions

None

Description

Summary

The CacheHandler class creates a cache file to store the auth token here: /~https://github.com/spotipy-dev/spotipy/blob/master/spotipy/cache_handler.py#L93-L98

The file created has rw-r--r-- (644) permissions by default, when it could be locked down to rw------- (600) permissions. I think 600 is a sensible default.

image

Details

This leads to overly broad exposure of the spotify auth token. If this token can be read by an attacker (another user on the machine, or a process running as another user), it can be used to perform administrative actions on the Spotify account, depending on the scope granted to the token.

PoC

Run an application that uses spotipy with client creation like this:

from pathlib import Path
import spotipy
from os import getenv

def create_spotify_client(client_id: str, client_secret: str) -> spotipy.Spotify:
    """Create and return an authenticated Spotify client.

    Args:
        client_id: Spotify API client ID
        client_secret: Spotify API client secret

    Returns:
        An authenticated Spotify client instance
    """
    cache_path = Path.home() / ".cache" / "spotify-backup/.auth_cache"
    cache_path.parent.mkdir(parents=True, exist_ok=True)
    cache_handler = spotipy.cache_handler.CacheFileHandler(cache_path=str(cache_path))

    client = spotipy.Spotify(
        auth_manager=spotipy.oauth2.SpotifyOAuth(
            client_id=client_id,
            client_secret=client_secret,
            redirect_uri="http://localhost:8000/callback",
            cache_handler=cache_handler,
            scope=[
                "user-library-read",
                "playlist-read-private",
                "playlist-read-collaborative",
            ],
        )
    )

    return client

create_spotify_client()

And then check the file permissions on the cache file that was created with:

$ ls -la ~/.cache/spotify-backup/.auth_cache`
.rw-r--r--. alichtman alichtman 562 B Thu Feb 20 02:12:33 2025  /home/alichtman/.cache/spotify-backup/.auth_cache

If this issue is combined with another misconfiguration, like having o+r permissions set on your home directory, an attacker will be able to read this file and steal this auth token.

Good defense in depth would be to restrict read permissions on this cache file that contains an auth token

Impact

Potential exposure of Spotify auth token to other users with access to the machine. A worst case scenario is if the token is granted all permissions, and can be used to do any of:

  • exfiltrate spotify likes / saved playlists
  • delete your content
  • modify your content w/o your permission

If someone were to discover an RCE in Spotify that you could trigger on a machine by having a song played (or song metadata parsed or something), this auth token could maybe be used to add a song to a playlist, or control playback (allowing further exploitation).

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 Local
Attack Complexity Low
Attack Requirements None
Privileges Required Low
User interaction None
Vulnerable System Impact Metrics
Confidentiality High
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:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

CVE ID

CVE-2025-27154

Weaknesses

Credits