How to carry out a cybersecurity audit? 5 steps to optimize your security

In France, one company in two was the victim of a cyber attack in 2023 (source: data.gouv.fr), and this trend is set to continue, with an 11-point increase in 2024 (source: Docaposte's 2024 Cybersecurity Barometer).

Faced with this persistent cyber threat, companies need to implement cybersecurity strategies to protect themselves against the theft of confidential data, avoid financial losses (one company in eight reports costs of more than230,000, according to the same barometer) and damage the integrity of their information systems (IS) and their reputation.

It is essential to carry out a regular cybersecurity audit to assess the effectiveness of strategies in place and identify potential vulnerabilities. And this, even if 72% of them believe they are doing enough to protect themselves. This time, it's the French National IS Security Agency that tells us so.

This audit also enables companies that do not yet have a cybersecurity system to identify and remedy weaknesses in their IS. So, what is a security audit, and how do you go about it? Find out in this article. 🤓

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What is a cybersecurity audit?

Definition and importance

An IT security audit is a systematic, independent and documented process designed to evaluate theeffectiveness of the systems, rules and protocols implemented to ensure corporate security and digital compliance.

🗓️ Carried out at least once a year by experts, each cybersecurity audit gives rise to a detailed action plan to :

1. correct detected vulnerabilities,
2. and secure information systems in an appropriate and proportionate manner.

The cybersecurity audit is of prime importance for the company, faced daily with increasingly sophisticated cyberattacks, thanks in particular to new technologies and AI.

Why carry out a cybersecurity audit? 10 objectives

The digital world is constantly evolving. Businesses are regularly integrating new technologies, enabling the various players to be more agile and simply access the information they need both locally and in mobile situations. The spread of teleworking and nomadism is contributing to the physical and virtual expansion of connection points to corporate networks, thereby multiplying the number of entry points for cybercriminals.

Against this backdrop, a cybersecurity audit helps to:

1. Identify IS vulnerabilities as a whole,

2. Anticipate risks,

3. Reassess the relevance of cybersecurity strategies,

4. Improve digital security equipment and software,

5. Update systems' regulatory compliance,

6. Update practices,

7. Raise awareness of cyber risks among all employees, and pass on best practices,

8. Make concrete recommendations on all aspects of cybersecurity,

9. Optimize cybersecurity budgets and resources,

10. Reduce the financial costs and damage caused by acts of cyber-malware (data theft, business interruption, impact on the company's reputation).

What are ANSSI's audit recommendations?

The French National Agency for Information Systems Security (ANSSI), a benchmark in cybersecurity and cyberdefenseand cyberdefense, recommends regular, comprehensive cybersecurity audits. With this in mind, it has published a set of requirements for information systems security audit providers.

According to ANSSI, a cybersecurity audit must :

• measure the level of IS compliance in terms of security (best practices, benchmarks, standards, etc.),

• assess the level of IS security, based on various audits (organizational and physical, architecture, configuration and source code, intrusion tests),

• correct IS non-compliance and vulnerabilities by implementing appropriate security measures.

Types of cybersecurity audits to consider

In line with ANSSI recommendations, a cybersecurity audit covers the entire company information system.

Technical audit: analysis of systems and networks

The technical cybersecurity audit involves an in-depth analysis of :

• Network architecture (tree structure, cabling, wireless connection, interconnection equipment, firewall),

• Operating systems installed on servers and user workstations (fixed and mobile),

• Applications and databases.

Strategic audit: security policy assessment

Assessing security policies concerns the overall architecture of a company's information system, the organization of teams, levels of expertise, processes, risk management and the way in which risks are anticipated. Yes, all that. 😮‍💨

During this audit, the auditors :

• analyze documentation relating to safety policies,

• conduct interviews with managers,

• evaluate the organization and technical systems deployed,

• establish points of comparison with security guidelines and standards.

Penetration testing: identifying vulnerabilities

This stage of the cybersecurity audit involves identifying vulnerabilities that could be exploited. These tests take place in several phases:

• Gathering accessible information to model the possible attack surface,

• Analysis of connection ports, services accessible from the Internet, cloud services, websites, mail servers and access points such as VPNs (virtual private networks) and DMZs (isolated sub-networks), but also of the vulnerabilities that can be exploited.network architecture to identify possible access points on the local network, connected objects or services hosted in private clouds,

• Simulation of real-life attacks targeting identified vulnerabilities through code injection, session hijacking, cross-site scripting (XSS, web page content injection), etc.

Compliance audit: ensuring compliance with regulatory standards

The purpose of this audit is to identify non-compliances and to detect discrepancies between current company practices and data security and protection requirements. The audit also comprises several stages:

• Gathering information and analyzing procedures,

• Assessment of the quality and efficiency of internal controls,

• Highlighting deviations from regulations and risks,

• Assessment and recommendations.

📑 The authoritative standards and benchmarks in this field are:

• ISO/IEC 27001, the global reference standard for information security management systems (ISMS) ,

• General Data Protection Regulation (RGPD), framing data processing on European territory,

• NIS 2 Directive (network and information systems security), aimed at reinforcing the level of cybersecurity of European companies and institutions...

5 steps to audit and strengthen your IS security

Step 1: Prepare your cybersecurity audit

The aim of this first stage of the cybersecurity audit is to determine the objectives, scope and modalities of the process.

Draw up clear specifications for the audit

Drawing up a set of specifications makes it possible to

• clearly set out the main objectives of the cybersecurity audit,
• verify compliance of data processing with the RGPD,
• assess procedures for updating and correcting vulnerabilities...

The scope of the audit is also defined in the specifications. It may concern the entire company information system, or only specific areas such as network and telecoms infrastructures, systems and backup, cloud instances, security policies.

Depending on the context, the specifications may also specify the types of threat requiring particular attention, such as phishing, software and system vulnerabilities, endpoints...

The specifications must also include a specific, operational backup and business continuity plan. This plan must be capable of restoring normal operation of the systems affected by the intrusion tests in a very short space of time.

The audit plan detailed in the specifications should also indicate the timetable and main stages of the audit, and identify the team leader and the various people involved.

Choose the right audit provider

The choice of service provider is based on references, proven expertise, and the methods, techniques and equipment available to carry out the work.

Use the requirements framework published by ANSSI to establish the criteria for choosing your service provider.

Involve stakeholders in the process

The team mobilized to carry out the cybersecurity audit must bring together external and internal auditors to combine both :

• A high level of technical expertise and the objectivity of external contributors,

• Precise knowledge of the information system they have developed and operate on a daily basis.

Step 2: Conducting the cybersecurity audit

Collect the data

The initial phase of the security audit consists of gathering all the documents that can be used for the purpose:

• documentation relating to the company's security policy,
• service continuity plans (response to attacks, escalations, etc.),
• network diagram (visual representation of the network and its components),
• precise inventory of IT assets.

If this is not the first cybersecurity audit, previous audit reports and documented events should also be included.

Penetration testing: white box vs. black box

There are two methods for conducting penetration tests as part of a cybersecurity audit:

• The white box pentest,

• black box pentest.

👉 As part of a white-box penetration test, all information is transmitted transparently to the test manager, including architecture documents, administrator access to servers, configurations and source code, privileges associated with legitimate IS user profiles retained as potential attackers.

👉 As part of a black-box penetration test, the auditors have no information on the audited system, with the exception of IP addresses, URLs or domain names.A black-box intrusion test simulates an attack similar to that carried out by a person totally outside the company, whereas a white-box intrusion test simulates an attack similar to that carried out by a person totally outside the company.a white-box penetration test identifies vulnerabilities that may not be visible in a conventional penetration test.

Step 3: Analyze audit results

Interpret the results to identify vulnerabilities

Following the cybersecurity audit, the auditors are asked to provide an overall assessment of the compliance and security of the audited information system. of the audited information system, contextualizing each identified vulnerability (test procedure, results).

Assess the criticality of identified vulnerabilities

The cybersecurity audit report must propose a severity level for each non-compliance and vulnerability, based on a pre-defined scale. For each problem identified, recommendations are drawn up, including one or more solutions proportionate and adapted to the level of risk.

Step 4: Drawing up a post-audit action plan

Prioritize actions according to risks

The report issued at the end of the cybersecurity audit enables internal teams to plan the course of future operations. A precise timetable establishes a prioritization according to the level of criticality, and details the resources to be mobilized and the actions to be taken to correct these anomalies.

Implement a reinforced cybersecurity policy

The recommendations resulting from the cybersecurity audit contribute to the development of the company's security and compliance policy. The IT Department can then integrate them into a reinforced strategy, taking into account the evolution of cyber-attacks, IS vulnerabilities and the solutions to be put in place. The cybersecurity audit gives companies all the elements they need to establish a resilient cybersecurity policy. ✅

Plan awareness-raising sessions for employees

Alongside the actions undertaken by IT teams, it's important to plan awareness sessions for employees. They provide an opportunity to review the results of the cybersecurity audit, and to make teams aware of the potential damage threatening the company when security and compliance measures are not applied.

It's also an opportunity to update the best practices to be applied so as not to jeopardize the entire IS!

Step 5: Monitoring and continuous improvement of cybersecurity

Update security and incident response protocols

In addition to the priority actions set out in the post-audit action plan, the teams in charge of IT security and data protection need to review the company's cybersecurity policies. This involves integrating different practices and processes for securing the information system (access control, network organization, etc.) into the existing system.(access control, network organization with the creation of DMZs, evolution of solutions deployed on client workstations).

To optimize monitoring and alert procedures, and adapt responses to more systematic, personalized and even stealthier attacks, it is necessary to update the procedures to be followed in the event of an attack or intrusion, establish different scenarios depending on the attack, and define everyone's role.

Regularly assess the state of cybersecurity

IT teams draw on the history of actions carried out as part of the cybersecurity audit to reinforce monitoring of network and system activities. Regular vulnerability scans, systematic installation of patches and security updates are necessary to respond effectively to evolving cyber threats.

Integrate cybersecurity into corporate culture

Cybersecurity and information system protection are the responsibility of everyone in the company. Of course, at different levels, but for a cybersecurity system to be effective, and to know how to react in the event of an attack or unintentional error to know how to react in the event of an attack or unintentional error, users need to learn how to incorporate the right reflexes into their day-to-day work , through regular information meetings and awareness-raising on best practices.

Everyone involved needs to be informed of the outcome of the cybersecurity audit, so as to feel empowered.

What tools can facilitate the audit process?

Experts in charge of cybersecurity audits in different areas of information systems use a variety of tools:

• Vulnerability scanners to detect vulnerabilities in systems, applications and networks,

• Penetration testing tools to simulate attacks,

• Network analysis and traffic monitoring tools,

• Compliance auditing and rights analysis tools,

• Cybersecurity audit reporting and report generation tools...

What are the common mistakes to avoid during an audit?

An enterprise cybersecurity audit requires rigorous project management to ensure that mistakes do not jeopardize the objectives. The main mistakes to avoid are :

• Poor preparation of the upstream phases of the audit,

• Rough drafting of specifications,

• Lack of rigor in the choice of service provider,

• Lack of rigor in data collection and analysis,

• Failure to define a precise schedule for the various phases,

• Failing to involve internal teams in the audit and reporting of results,

• Neglecting the compliance of the information system with regard to the processing and storage of confidential data,

• Produce inaccurate reports and define inadequate corrective actions.

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Investing in security for your company's future

Corporate cybersecurity has become essential in the face of increasing cyberthreats, which have multiple consequences, both financially and in terms of your company's reputation and long-term survival. To preserve the integrity of your information systems and data, you need to :

• Invest in state-of-the-art cybersecurity hardware and software, such as EDR (Endpoint Detection and Response) patch management software, a new-generation firewall and intrusion detection probes,

• Regularly update your IT assets,

• Conduct regular cybersecurity and compliance audits,

• Implement an agile and resilient cybersecurity strategy,

• Involve all your employees and make them aware of good cybersecurity practices.

Investing in IT security is the best way to protect your company's IT assets, reputation and competitiveness in increasingly exposed environments.