CVE-2023-37474

All versions before 1.8.2 have a path traversal vulnerability, allowing an attacker to download unintended files from the server.

Details

Unauthenticated users were able to retrieve any files which are accessible (according to OS-level permissions) from the copyparty process. Usually, this is all files that are readable by the OS account which is used to run copyparty.

The vulnerability did not make it possible to list the contents of folders, so an attacker needs to know the full absolute path to the file, or the relative path from where copyparty is installed.

Some methods of running copyparty (prisonparty, the nix package, and docker) had a mitigating effect, mostly reducing the attack scope to files inside copyparty volumes, and possibly the copyparty config file.

Checking for attacks

Please keep in mind that, if an attacker were to find a way to overwrite the logs, for example by discovering the password to another service with sufficient privileges, then the following approaches cannot be trusted.

if copyparty was only accessible through a reverse proxy, then all attacks would be visible in the webserver access-log as URLs which contain both .cpr/ and %2F

• nginx:

  (gzip -dc access.log*.gz; cat access.log) | sed -r 's/" [0-9]+ .*//' | grep -E 'cpr/.*%2[^0]' | grep -vF data:image/svg
  

However, if copyparty was directly accessible from the internet, then any successful attacks (file retrievals) would unfortunately leave no trace. That said, it is very probable that an attacker would make at least one invalid attempt, which would become apparent in the copyparty server log, detectable with grep -aE '(Errno|Permission).*\.cpr/' revealing the following:

• python2 example: [IOError] [Errno 13] Permission denied: '/etc/shadow', .cpr//etc/shadow
• python3 example: [PermissionError] [Errno 13] Permission denied: b'/etc/shadow', .cpr//etc/shadow

Providing an exact command for this approach is difficult, as it depends on how copyparty is deployed;

• if copyparty was running as a systemd service: journalctl -am | grep -aE '(Errno|Permission).*\.cpr/'
• if copyparty was logging to a compressed file: xz -kdc thefilename.xz | grep -aE '(Errno|Permission).*\.cpr/'
• if the copyparty log is available in a plaintext file: grep -aE '(Errno|Permission).*\.cpr/' thefilename.txt

PoC / attack example

curl -sik http://127.0.0.1:3923/.cpr/%2Fetc%2Fpasswd
curl -sik http://127.0.0.1:3923/.cpr/..%2F..%2F..%2F..%2F..%2Fetc%2Fpasswd

Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.

CVE-2023-37474 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.8.2); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2023-37474? CVE-2023-37474 is a high-severity path traversal vulnerability in copyparty (pip), affecting versions < 1.8.2. It is fixed in 1.8.2. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
2. How severe is CVE-2023-37474? CVE-2023-37474 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of copyparty are affected by CVE-2023-37474? copyparty (pip) versions < 1.8.2 is affected.
4. Is there a fix for CVE-2023-37474? Yes. CVE-2023-37474 is fixed in 1.8.2. Upgrade to this version or later.
5. Is CVE-2023-37474 exploitable, and should I be worried? Whether CVE-2023-37474 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2023-37474 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2023-37474? Upgrade copyparty to 1.8.2 or later.