curl / Development / Security Process

curl security process

This document describes how security vulnerabilities should be handled in the curl project.

Publishing Information

All known and public curl or libcurl related vulnerabilities are listed on the curl website security page.

Security vulnerabilities should not be entered in the project's public bug tracker.

Vulnerability Handling

The typical process for handling a new security vulnerability is as follows.

No information should be made public about a vulnerability until it is formally announced at the end of this process. That means, for example, that a bug tracker entry must NOT be created to track the issue since that will make the issue public and it should not be discussed on any of the project's public mailing lists. Also messages associated with any commits should not make any reference to the security nature of the commit if done prior to the public announcement.

security (at curl dot se)

This is a private mailing list for discussions on and about curl security issues.

Who is on this list? There are a couple of criteria you must meet, and then we might ask you to join the list or you can ask to join it. It really is not a formal process. We basically only require that you have a long-term presence in the curl project and you have shown an understanding for the project and its way of working. You must have been around for a good while and you should have no plans of vanishing in the near future.

We do not make the list of participants public mostly because it tends to vary somewhat over time and a list somewhere will only risk getting outdated.

Publishing Security Advisories

  1. Write up the security advisory, using markdown syntax. Use the same subtitles as last time to maintain consistency.

  2. Name the advisory file after the allocated CVE id.

  3. Add a line on the top of the array in curl-www/docs/vuln.pm.

  4. Put the new advisory markdown file in the curl-www/docs/ directory. Add it to the git repository.

  5. Run make in your local web checkout and verify that things look fine.

  6. On security advisory release day, push the changes on the curl-www repository's remote master branch.

HackerOne

Request the issue to be disclosed. If there are sensitive details present in the report and discussion, those should be redacted from the disclosure. The default policy is to disclose as much as possible as soon as the vulnerability has been published.

Bug Bounty

See BUG-BOUNTY for details on the bug bounty program.

Not security issues

This is an incomplete list of issues that are not considered vulnerabilities.

Small memory leaks

We do not consider a small memory leak a security problem; even if the amount of allocated memory grows by a small amount every now and then. Long-living applications and services already need to have counter-measures and deal with growing memory usage, be it leaks or just increased use. A small memory or resource leak is then expected to not cause a security problem.

Of course there can be a discussion if a leak is small or not. A large leak can be considered a security problem due to the DOS risk. If leaked memory contains sensitive data it might also qualify as a security problem.

Never-ending transfers

We do not consider flaws that cause a transfer to never end to be a security problem. There are already several benign and likely reasons for transfers to stall and never end, so applications that cannot deal with never-ending transfers already need to have counter-measures established.

If the problem avoids the regular counter-measures when it causes a never- ending transfer, it might be a security problem.

Not practically possible

If the flaw or vulnerability cannot practically get executed on existing hardware it is not a security problem.

API misuse

If a reported issue only triggers by an application using the API in a way that is not documented to work or even documented to not work, it is probably not going to be considered a security problem. We only guarantee secure and proper functionality when the APIs are used as expected and documented.

There can be a discussion about what the documentation actually means and how to interpret the text, which might end up with us still agreeing that it is a security problem.

Local attackers already present

When an issue can only be attacked or misused by an attacker present on the local system or network, the bar is raised. If a local user wrongfully has elevated rights on your system enough to attack curl, they can probably already do much worse harm and the problem is not really in curl.

Experiments

Vulnerabilities in features which are off by default (in the build) and documented as experimental, are not eligible for a reward and we do not consider them security problems.

URL inconsistencies

URL parser inconsistencies between browsers and curl are expected and are not considered security vulnerabilities. The WHATWG URL Specification and RFC 3986+ (the plus meaning that it is an extended version) are not completely interoperable.

Obvious parser bugs can still be vulnerabilities of course.

Visible command line arguments

The curl command blanks the contents of a number of command line arguments to prevent them from appearing in process listings. It does not blank all arguments even if some of them that are not blanked might contain sensitive data. We consider this functionality a best-effort and omissions are not security vulnerabilities.