Holiday out-of-office messages can facilitate phishing attacks against a company

An automatic email reply activated during the holidays can become a useful source of information for cybercriminals. Apparently innocent messages such as “I’m on holiday” can reveal when an employee is absent, who is replacing them and how to contact that person, as well as providing details about a company’s departments or internal structure.

The risk does not lie in using an automatic reply, but in the amount of information it contains. If a message states that a finance manager will be away until a specific date and identifies who will handle their duties during that period, an attacker can use this data to create a more credible impersonation attempt.

The warning comes from Qualiteasy Internet Solutions, the exclusive distributor in Spain of Faronics solutions, which points out that overly detailed out-of-office messages can facilitate social engineering campaigns. The company recommends limiting the information shared in external replies and retaining only essential details.

A source of context for preparing fraud

The data included in an “out of office” message can fuel different types of attacks. These include targeted phishing, CEO fraud and Business Email Compromise (BEC)—techniques that seek to deceive employees through communications that appear to come from a known person or a legitimate organisation.

For example, a cybercriminal could take advantage of a manager’s absence to impersonate them when contacting another employee. They could also contact the person replacing them and use real information about the organisation to request an action, ask for documentation or attempt to redirect a task.

Information from an automatic reply can be particularly useful when combined with other data available about the company and its employees. The name of a manager, their role, the exact period of absence and the replacement contact make it possible to build a context that can make a fraudulent message more convincing.

“The most sophisticated attacks do not always start with a technical vulnerability. They can begin by gathering apparently irrelevant information about a company and its employees. An overly detailed holiday message can provide precisely the context an attacker needs to make a fraudulent email appear credible,” says Ignasi Nogués, Chief Growth Officer at Qualiteasy Internet Solutions.

The human factor, a key component

The recommendation comes against the backdrop of the continuing importance of the human factor in organisational security. According to Verizon’s 2025 Data Breach Investigations Report, 60% of the breaches analysed involved some human element.

The report includes errors, compromised credentials and social engineering techniques within this area. In this context, an automatic reply does not in itself constitute a security breach, but it can provide information that facilitates an attempt to deceive a company’s employees.

Information about absences, replacements and responsibilities can help an attacker identify who is available, who makes a decision or which person may have access to certain processes. The more precise this information is, the easier it may be to design a communication that appears normal within the company’s daily operations.

What information should be avoided

To reduce exposure, experts recommend that external out-of-office messages be brief and neutral. There is no need to specify the exact holiday dates, the employee’s destination, their telephone number or the name and email address of the person replacing them.

It is also advisable to avoid any reference to customers, projects or specific tasks. This data can give a stranger a broader view of the company’s activities and of the relationships between its employees, departments and partners.

When it is necessary to provide an alternative contact, one option is to use generic organisational addresses, such as those for support or customer service departments. This makes it possible to continue handling enquiries without directly exposing the identity and details of a specific person.

Corporate platforms also allow different replies to be configured for internal and external users. This makes it possible to share operational information only with those who genuinely need it, while contacts outside the organisation receive a more limited message.

“It is not about eliminating automatic messages, but about applying the same principle we use with any other corporate information: share only what is necessary. The less data a stranger has about who is available, who makes a decision and when someone is absent, the harder it will be to build a convincing social engineering attack,” Nogués adds.

Reviewing security during the holiday period

The holiday period can also be used to review other basic security measures within the company. These include multifactor authentication, access permissions, backups and employee training.

Training should help identify phishing attempts, impersonation attacks and other suspicious communications. The aim is for employees to detect warning signs before replying to a message, providing information or carrying out an action requested by a supposed manager, supplier or colleague.

Reviewing access permissions makes it possible to check that each employee has only the authorisations necessary for their duties. Backups, meanwhile, are a basic measure for protecting information and facilitating recovery after certain incidents.

Multifactor authentication adds an additional layer of protection to corporate accounts. Although it does not prevent every fraud attempt, it makes it more difficult for access to depend solely on a compromised password.

Sharing only essential data

A holiday automatic reply may seem like a routine practice without consequences. However, the data it contains can become another element of an attack when combined with information obtained from other sources.

The recommendation is not to stop using out-of-office messages, but to review their content before activating them. Do not provide more information than necessary, avoid precise dates and personal details, and use generic corporate contacts: these are simple measures for reducing the information available to a potential attacker.

In cybersecurity, apparently innocent information can have value when incorporated into a social engineering strategy. The “I’m on holiday” message shows how an everyday practice can reveal data about a company’s availability, responsibilities and internal organisation, and how limiting these details can make fraud preparation more difficult.