Fix sensitive data exposure: Change access to `thug-profiler.log` file

[fazledyn-or]

Details

While triaging your project, our bug fixing tool generated the following message(s)-

In file: thug.py, there is a method: main that creates a temporary file using a hard coded path to a public writable directory. This exposes the temporarily created file to race condition attacks. An attacker can access, modify or even delete a file. iCR suggested that a temporary file should be created using a safe API in a secured directory instead.

Notes

For example, let's take the following script as an example -

import os

def opener(path, flags):
    return os.open(path, flags, 0o640)

with open('/tmp/thug-profiler-good.log', encoding = 'utf-8', mode = 'w', opener = opener) as fd:
    fd.write("*** Some things ***")

with open('/tmp/thug-profiler-bad.log', encoding = 'utf-8', mode = 'w') as fd:
    fd.write("*** Some things ***")

After executing the script, we'd find two files called thug-profiler-good.log and thug-profiler-bad.log in the /tmp directory as below -

$ ls -la /tmp/thug-profiler-*
-rw-rw-r-- 1 ataf ataf 30 Oct 16 16:52 /tmp/thug-profiler-bad.log
-rw-r----- 1 ataf ataf 28 Oct 16 16:52 /tmp/thug-profiler-good.log

Here, we can see that the thug-profiler-bad.log file was created with permission 664 whereas the new thug-profiler-good.log file is created with permission 640.

Since /tmp is a public folder that's accessible from everyone, it's recommended that special measures should be taken so that files written to this directory can't be overridden or removed by others.

Changes

Implemented an opener() method that opens the file with permission 644 (rw-r--r--)

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Sponsorship and Support

This work is done by the security researchers from OpenRefactory and is supported by the Open Source Security Foundation (OpenSSF): Project Alpha-Omega. Alpha-Omega is a project partnering with open source software project maintainers to systematically find new, as-yet-undiscovered vulnerabilities in open source code - and get them fixed – to improve global software supply chain security.

The bug is found by running the Intelligent Code Repair (iCR) tool by OpenRefactory and then manually triaging the results.

[buffer]

Thanks for your report. I really appreciate!

FYI I opted for a different and more cross-platform approach than the one you proposed. You can take a look at the fix at [1].

Thanks again!

[1] https://github.com/buffer/thug/commit/b28ffa5b9755a3b2a3548ee4760e69f2701645e6

[fazledyn-or]

Thanks for your report. I really appreciate!

FYI I opted for a different and more cross-platform approach than the one you proposed. You can take a look at the fix at [1].

Thanks again!

[1] b28ffa5

Yup. NamedTemporaryFile or mkstemp is another approach to go. Glad to be of help!