Vulnerability disclosure

Vulnerability Disclosure Ecosystem

Responsible vulnerability disclosure

By Jonathan Armas | October 25, 2018 | Category: Hacking

An information security vulnerability is a flaw or a weakness in a system or application that a malicious attacker could exploit, and could result in a compromise of the confidentiality, integrity or availability of both software and hardware systems.

We, as Security Testers (or pentesters, white hat hackers), every day find new vulnerabilities in our clients' software, systems, and procedures. If someone discloses these, before they’re fixed, the result could be as great a problem for the users as it is for the company.

Identifying and fixing vulnerabilities is crucial, and the process of disclosure of vulnerabilities is a part of this ecosystem. However, performing security tests on systems that we do not have the authorization for, could result in legal issues for the researcher. This risk might be reduced if we apply good practices when we are going to disclose a vulnerability.

To understand how we should disclose vulnerabilities, we need to know who the actors are who participate in this process:


Individuals or organizations who find vulnerabilities. They could be researchers, security companies, users, as well as others.


They develop and maintain information system products that may be vulnerable. This includes both large vendors of software and small open-software development groups.


They manage the vendor’s response to vulnerabilities. They serve as unbiased, independent evaluators of severity and may act as an intermediary for communicating with the public.


Anyone using a vendor’s product that could be affected by the vulnerability.

Responsible vulnerability disclosure

To avoid legal issues and to have a successful resolution of the vulnerabilities, we need to follow a structured plan. The life cycle of a vulnerability disclosure is as follows:

Vulnerability Cycle
Figure 1. Vulnerability Cycle

A security researcher, organization or individual tries to find new vulnerabilities on a system or application. They test and validate the vulnerability by developing a repeatable process to verify its effects.

Then, they communicate what they have found to the software vendor. This could be direct communication to the vendor, or through a coordinator like a CSIRT-Computer Security Incident Response Team.

Later, the vendor investigates the vulnerability. If it’s validated, they start to work in a patch or countermeasure. When finished, they release the new fix and the information about the vulnerability.

Reporting the vulnerability is the most important part of the process. In this step, the expertise of both vendor and researcher are put to the test. Here, we can establish some good practices a security tester can use when reporting a vulnerability:

  • Alert the company

  • If alerting the company fails, try contacting multiple people from the company’s chain of command, several different times.

  • If altering the vendor fails, try contacting the national CSIRT.

  • If all else fails, contact the CSIRT with a full disclosure.

Each step has a time interval. There are multiple methodologies that have different waiting times. Some have a 45-day disclosure policy, others 90 days since the notification, which is what we recommend. In any case, you need to be flexible, as these times might change. Communication is key when managing these events.

The vendor should provide status updates about the vulnerability and try to resolve it within the stated timeframe. They can ask for a grace period during which the finder and the coordinator won’t release the details of the vulnerability; it all depends on the severity of the flaw or the difficulty involved with resolving it.

When the vulnerability is fixed, the vendor has to credit the finder. Usually, this is done by putting the finder on the patch notes. Some vendors have bug bounty rewards where they give money to the finders.

Vulnerability disclosure is a delicate process, but also a very rewarding one for all parties. It is well known that nowadays there are multiple security vulnerabilities and customer/company information disclosure can be exploited by malicious attackers. A benign environment where security researchers and vendors can team-up together to find and fix critical vulnerabilities before they can affect someone is a win-win situation.