CVE-2024-23334
Description
A flaw was found in aiohttp. When using aiohttp as a web server and configuring static routes, it is necessary to specify the root path for static files. Additionally, the option 'follow_symlinks' can be used to determine whether to follow symbolic links outside the static root directory. When 'follow_symlinks' is set to True, there is no validation to check if a given file path is within the root directory. This issue can lead to a directory traversal vulnerability, resulting in unauthorized access to arbitrary files on the system, even when symlinks are not present.
Statement
This vulnerability has been rated as having a moderate impact. There is a non-default precondition which is required to exploit it: the follow_symlinks setting needs to be enabled.
Mitigation
If using follow_symlinks=True outside of a restricted local development environment, disable the option immediately. This option is NOT needed to follow symlinks that point to a location within the static root directory; it is only intended to allow a symlink to break out of the static directory. Even with this CVE fixed, there is still a substantial risk of misconfiguration when using this option on a server that accepts requests from remote users.
Additionally, aiohttp has always recommended using a reverse proxy server (such as nginx) to handle static resources and not to use these static resources in aiohttp for production environments. Doing so also protects against this vulnerability, and is why we expect the number of affected users to be very low.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.9 | 7.5 | 5.9 |
| Attack Vector | Network | Network | Network |
| Attack Complexity | High | Low | High |
| Privileges Required | None | None | None |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | High | High | High |
| Integrity Impact | None | None | None |
| Availability Impact | None | None | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
cve.org: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Red Hat CVSS v3 Score Explanation
In order to exploit this flaw follow_symlinks has to be set to true, only then the directory traversal works. Such a measure is out of attackers control which is why attack complexity has been set to high.
Understanding the Weakness (CWE)
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
The attacker may be able to create or overwrite critical files that are used to execute code, such as programs or libraries.
Integrity
Technical Impact: Modify Files or Directories
The attacker may be able to overwrite or create critical files, such as programs, libraries, or important data. If the targeted file is used for a security mechanism, then the attacker may be able to bypass that mechanism. For example, appending a new account at the end of a password file may allow an attacker to bypass authentication.
Confidentiality
Technical Impact: Read Files or Directories
The attacker may be able read the contents of unexpected files and expose sensitive data. If the targeted file is used for a security mechanism, then the attacker may be able to bypass that mechanism. For example, by reading a password file, the attacker could conduct brute force password guessing attacks in order to break into an account on the system.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
The attacker may be able to overwrite, delete, or corrupt unexpected critical files such as programs, libraries, or important data. This may prevent the product from working at all and in the case of protection mechanisms such as authentication, it has the potential to lock out product users.
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