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And Don't Forget ISO/IEC 30111

Guidelines for the vulnerability handling processes

By Felipe Ruiz | February 12, 2021

A few days ago, I brought readers some highlights on the ISO/IEC 29147:2018 standard that guides us in the vulnerability disclosure processes. (If you haven’t read that post, for clarity and contextualization, I recommend that you do so before continuing with this one.) These processes mainly involve receiving security vulnerability reports as a vendor and releasing remediation advisories to all stakeholders. They are two points, beginning-ending, of a course of action between which it is necessary to address the vulnerabilities in your systems. As a vendor, you have to verify that what the reporter informed you of is a real security issue and, if so, you need to come up expeditiously with a solution. This is the topic covered by the ISO/IEC 30111:2019 standard, about which I will inform you in this post.

'Information technology -Security techniques- Vulnerability handling processes' is the name of this standard, which, like the ISO/IEC 29147, is in the ISO standards catalog in group 35 'Information technology,' subgroup 35.030 'IT Security (including encryption).' As stated in the introduction to this standard, it "describes processes for vendors to handle reports of potential vulnerabilities in products and services." Therefore, as may already be clear, everyone should use this standard in consonance with that one of vulnerability disclosure. Beyond the handling of reports, it also discusses requirements and recommendations for the procedures of examination, triage, and remediation of vulnerabilities.


As a preliminary step, vendors should create and maintain vulnerability handling policies for a commitment to the security of their products or services and the benefit of their customers or users. ISO suggests that vendors need to explicitly disclose their intentions to investigate and remediate security vulnerabilities to all interested parties. These policies should be continuously reviewed, updated, and improved by the managers of each organization. Part of the policies should be directed to vendors' staff to provide them with basic guidelines, roles, and responsibilities in handling reports and vulnerabilities. It is of utmost importance that all concerned persons also receive caveats to ensure the privacy of information about vulnerabilities prior to their remediation.

Organizational scheme

ISO recommends that vendors build their vulnerability handling processes and evaluate them frequently to be always well prepared to deal with reports and security issues. Every company should have a document where all these processes remain faithfully recorded for prospective replication and possible optimization. Besides, they should always contemplate an appropriate integration of these operations with their other procedures and ensure that the required resources for the intended outcomes are permanently available.

Companies prepared for handling vulnerabilities establish authorities or leaders to be aware of the internal processes, objectives, and organizational frameworks and make decisions at a management level. It is pertinent for these organizations to have points of contact for communications with internal departments and external parties concerned with the vulnerability disclosure and handling processes. Not to mention being ready to receive and respond to questions from customers and other interested individuals when information about security weaknesses has already been made public.

At this point, those units mentioned by ISO as 'product security incident response teams' (PSIRT) stand out. Apart from their activities as points of contact and supervisors of disclosure procedures, these teams may help with the vulnerability assessments of vendors' products and services. Their assistance should include tracking weaknesses or flaws found in third-party suppliers' software components that may impact the operations and assets of the vendors in consideration. In addition, PSIRT staff should understand the pertinence of maintaining confidentiality before vulnerability remediations are carried out and notifying 'product business divisions' for appropriate action.

Product business divisions, those that provide products or services to vendors' clients, are also responsible parties in vulnerability handling processes. These divisions receive vulnerability reports from PSIRT and should work with them in the development of remediations. After remediations are ready, the 'customer support divisions' are in charge of sending corresponding advisories to customers and other stakeholders, a matter of vulnerability disclosure processes, appearing in ISO/IEC 29147.

Vulnerability handling process

Now, as a guide for companies in establishing their vulnerability handling processes, let’s check what ISO shares for the phases of verification and remediation of vulnerabilities.

Figure 1. Photo by Kovah on Unsplash

Verification of vulnerabilities

After receiving a report of a potential vulnerability, the vendor has to verify it. Here’s where the investigation begins to confirm the weakness, determine the affected product or service, the security issue’s severity, and the root cause. If it is necessary, the vendor should request further evidence from the reporter. When verification shows that the vulnerability is a duplicate, has no security implications, or is in an obsolete or external product, the vulnerability handling process must be interrupted. Of course, if other vendors are compromised, the issue should be prudently reported to them.

It’s valuable —and companies should pay attention to it— ISO’s emphasis on the continuous change in the exploitability of weaknesses resulting from advances in attack techniques. Another essential aspect to consider in verifications, usually when various vulnerabilities have been reported, corresponds to prioritization. "Vendors may consider several factors in determining the relative urgency of producing a remediation, such as potential impact, likelihood of exploitation, and the scope of affected users." Finally, after the vulnerability verification, reporters should receive information about results.

Remediation of vulnerabilities

Vendors need to establish either partial or total remediations to the vulnerabilities they have already verified. While the remediation is expected to be generated quickly, vendors should maintain this in balance with the amount of testing required to ensure the product’s or service’s high quality. Fast and temporary remediations usually take place when the vulnerabilities show critical or high-risk levels for customers or users, which should receive constant assistance. In association with this, it may be necessary for vendors to disable at-risk applications or software temporarily.

Regarding the tests to be carried out with the remediations, vendors should guarantee evaluation on the corresponding platforms. Plus, their results should be sufficient proof of the absence of new vulnerabilities and operational and quality obstacles in products or services. A remediation that doesn’t work is one that needs to be rethought.

After releasing the vulnerability remediations, vendors should continue updating them until it is no longer required. On the other hand, with the information gained during the investigation, vendors should check their software and make proper renewals to prevent similar security weaknesses in their products or services.

To conclude, it is worth highlighting the monitoring activity for the vulnerability handling processes, suggested by ISO. Every company or vendor should always keep track of (and be ready to improve) the speed at which they respond with verifications and remediations. They should also supervise that their remediations are complete at the end of each case, in terms of dealing with the root causes of vulnerabilities, and that results are as expected. All of this, it is hoped, should go hand in hand with a confidential and secure treatment of vulnerability information and individuals' and organizations' sensitive data.

Would you like to know how Fluid Attacks can help you in your vulnerability handling processes? Do not hesitate to contact us!

PS: Several important details are missing in this post. If you’re really interested in vulnerability handling, we recommend that you read the entire ISO/IEC 30111:2019 document.

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