CVE-2023-49297

EUVD-2023-0292 · Published Dec 5, 2023

PyDrive2's unsafe YAML deserialization in LoadSettingsFile allows arbitrary code execution

Summary

Unsafe YAML deserilization will result in arbitrary code execution. A maliciously crafted YAML file can cause arbitrary code execution if PyDrive2 is run in the same directory as it, or if it is loaded in via LoadSettingsFile.

Details

The loader being imported from the yaml library is CLoader: https://github.com/iterative/PyDrive2/blob/30c0f487c0666c0d1944ef774107359f39adc2fa/pydrive2/settings.py#L5

This loader is then used to load a user supplied file: https://github.com/iterative/PyDrive2/blob/30c0f487c0666c0d1944ef774107359f39adc2fa/pydrive2/settings.py#L108-L121

CLoader is considered unsafe. It will allow any Python code inside of it to be executed. This loading behaviour also happens automatically, the file only needs to be present for this vulnerability to occur.

https://github.com/iterative/PyDrive2/blob/30c0f487c0666c0d1944ef774107359f39adc2fa/pydrive2/settings.py#L9

Reference: https://www.exploit-db.com/docs/english/47655-yaml-deserialization-attack-in-python.pdf

PoC

Create a malicious settings.yaml file:

!!python/object/new:os.system [echo poc]

Initialize a GoogleAuth object .

from pydrive2.auth import GoogleAuth

gauth = GoogleAuth()

Execute the code with the settings file present in your directory. The code inside the file will be executed:

[evan@ejedev PyDrive2]$ ls
CHANGES  client_secrets.json  CONTRIBUTING.rst  docs  examples  LICENSE  main.py  MANIFEST.in  pydrive2  pyproject.toml  pytest.ini  README.rst  settings.yaml  setup.py  tox.ini
[evan@ejedev PyDrive2]$ cat settings.yaml
!!python/object/new:os.system [echo poc]
[evan@ejedev PyDrive2]$ cat main.py 
from pydrive2.auth import GoogleAuth


gauth = GoogleAuth()
[evan@ejedev PyDrive2]$ python3 main.py 
poc

Alternatively, the file can be loaded in directly via pydrive2.settings.LoadSettingsFile

Impact

This is a deserilization attack that will affect any user who initializes GoogleAuth from this package while a malicious yaml file is present in the same directory. As it does not require it to be directly loaded through the code, only present, I believe this produces an extra element of risk.

Technologies

Iterative Pydrive2Pydrive2 Pydrive2

Weaknesses

CWE-502

CVSS scores

v3.13.3CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

MITRE ATT&CK

Inferred

Where this vulnerability fits in an attack

ReconImpact

Privilege Escalation

T1068Exploitation for Privilege Escalation

References

Potentially impacted assets

See if this affects your attack surface

Latest trending attack

Criticalyesterday

Google Brotli decoder - Remote Code Execution via compressed requests (Exploitation Check)

This control is the second step of the Patrowl response to CVE-2026-111497 (Node2Shell). It complements the first control of 22 October 2026, which focused on the Node.js runtime, and does not replace it. Why a second control CVE-2026-111497 is an out-of-bounds write in the Google Brotli decoder, the library that decompresses Brotli ("br") data. It was first published as a Node.js vulnerability, because Node.js bundles this decoder. Later publications showed that the flaw is in the library itself. Every product that embeds an affected version of the decoder is concerned, whatever its language or vendor. A public proof of concept demonstrates code execution. Any server that decompresses request bodies sent with "Content-Encoding: br" exposes the decoder to unauthenticated attackers. Known cases include Express 5 and NestJS 11 on Node.js, Koa and Fastify setups, Bun, Envoy and Istio with request decompression enabled, and any application or reverse proxy that decodes Brotli request bodies with an affected library. The flaw also works in the other direction. A malicious server can compromise an unpatched client that decodes a Brotli response, for example Node.js fetch(), Python clients (requests, httpx, aiohttp, Scrapy) with the Brotli or brotlicffi package, or libcurl builds with Brotli support. What this control checks Patrowl sends small, valid Brotli-compressed requests to each asset and observes whether the server decodes them. The check does not depend on the technology: it detects the behaviour, whatever the stack behind it. These requests are what any legitimate client could send. They never reach the vulnerable code path and cannot affect the availability of the service. How to read the result Potentially impacted means the asset decodes Brotli request bodies: the attack surface is exposed. It does not confirm that the asset is vulnerable. The version of the Brotli decoder in use is not visible from the outside. This check covers applications that parse request bodies on their root path. A Not impacted result does not rule out exposure on other routes, nor on the client side. Checking the versions on the servers remains the only exhaustive verification. Affected and fixed versions Google Brotli 1.0.3 to 1.2.0 are affected, fixed in 1.0.10, 1.1.1 and 1.2.1. Fixed releases of the main products embedding it: Node.js 22.23.4, 24.22.1 and 26.12.1 (end-of-life lines 20.x and older and 25.x receive no fix), Bun 1.4.4, Envoy 1.37.8, 1.38.6, 1.39.3 and 1.40.0, Istio 1.29.9, 1.30.6 and 1.31.2, Python Brotli 1.2.1 and brotlicffi 1.2.1.0. Products that link against the system library depend on the Brotli package of the Linux distribution. Recommendations Update every component that embeds the Brotli decoder (only real fix). Start with the assets flagged by this control. Restart the processes after the update. Rebuild containers, single-executable applications and appliances that bundle an affected runtime or library. Reduce the exposure until the update is deployed. Reject requests with "Content-Encoding: br" at the reverse proxy, load balancer or WAF, case-insensitively and including lists such as "gzip, br". On Envoy and Istio, disable request decompression for Brotli. Review outbound calls. List the features that fetch content from servers you do not control, and patch the services that host them first.