Account takeover attacks against businesses are increasing. According to research from Abnormal Security, 83% of organizations surveyed had been impacted by at least one account takeover attack in the previous year, and 26% reported facing an account takeover attempt every week. And in Proton’s SMB Cybersecurity Report, we found that 1 in 4 small businesses have been hacked despite their cybersecurity measures.
The financial impact can be severe, too. Research from IBM reports that data breaches involving vendor compromise and account takeover average nearly USD 5 million in costs, with containment timelines often exceeding 250 days.
That combination of frequency and impact helps explain why account takeover is so dangerous for businesses: attackers can simply sign in with legitimate credentials and begin operating from inside the organization, often before anyone realizes the account is no longer trustworthy.
In the UK, the government’s Cyber Security Breaches Survey 2025 report also shows that takeover attempts and compromised accounts form part of the wider incident picture. For businesses, that makes account takeover more than a login issue. It is an identity security, fraud, and business continuity risk.
What is an account takeover attack?
How account takeover differs from traditional attacks
The most common account takeover methods
Why business accounts are high-value targets
Detection signals businesses should watch out for
The business impact of account takeover
Your practical response plan for a suspected account takeover
Building a stronger security culture around account access
How Proton Pass for Business reduces account takeover risk
What is an account takeover attack?
Cybercriminals launch account takeover attacks by gaining unauthorized access to a legitimate account and then using it for malicious purposes. In business environments, that usually means obtaining an employee’s password, intercepting their authentication flow, or otherwise gaining valid access to a work account.
Once inside, an attacker can read internal communications, change account settings, move into connected apps, export confidential files, or impersonate the employee in conversations with colleagues, vendors, or customers. Because the attacker has gained valid access rather than forcing their way in through a visibly broken system, the activity looks like business as usual.
This is what makes business account compromise so dangerous. An attacker may appear to be a normal user until damage is already underway.
How account takeover differs from traditional attacks
Account takeover is so disruptive because it isn’t as easy to spot as the kind of obvious attack or breach many teams expect.
Business security teams often look for malware(nytt fönster), exploited vulnerabilities, corrupted systems, or suspicious code execution. In an account takeover incident, no system may have been breached in the usual sense because the attacker has used legitimate credentials and ordinary sign-in flows.
This difference is important because teams need to look for credential abuse rather than perimeter intrusion. When an attacker signs in using the same login page as everyone else using valid credentials, the activity doesn’t appear suspicious in isolation.
Detection then depends less on spotting technical issues and more on noticing unusual behavior, such as strange login patterns, unexpected password resets, or abnormal access requests.
In other words, account takeover often succeeds by abusing the organization’s normal trust model.
The most common account takeover methods
Attackers can use several well-established methods to gain access to business accounts. Some are opportunistic, while others are highly targeted.
Credential stuffing
Credential stuffing happens when attackers take usernames and passwords leaked in data breaches and test them against other services. This works because people often reuse passwords across both personal and work accounts.
This makes unique passwords one of your organization’s best defenses against account takeover. Proton’s Data Breach Observatory shows that names and email addresses appear in nearly 9 out of 10 breaches, while passwords are exposed in 47% of incidents. When those credentials are reused across services, one breach quickly creates account takeover risk.
Phishing
Phishing remains one of the most common routes into business accounts. It can be used to steal passwords, session tokens, or MFA approvals, all of which can feed directly into account takeover.
SIM swapping
SIM swapping happens when an attacker convinces a mobile carrier to transfer a victim’s number to a SIM card they control. If a business still relies heavily on SMS-based authentication, then attackers can easily intercept login codes.
To protect against sim-swapping, two-factor authentication (2FA) methods are much more secure and suitable for higher-risk business accounts.
2FA fatigue and session theft
Even when 2FA is enabled, attackers may try to wear users down with repeated approval prompts or steal session tokens through phishing and malware. 2FA is essential, but it isn’t sufficient on its own.
Password spraying
Password spraying is a type of brute force attack(nytt fönster), where attackers try a set of commonly used passwords across many accounts. Instead of hammering one user with hundreds of guesses, they test weak defaults like “Welcome123!” or predictable company-based patterns against a wider pool of employees.
Why business accounts are high-value targets
Business accounts are attractive because of the data and funds they potentially hold. A compromised email account can enable business email compromise: for example, business payment fraud is a scam in which criminals tailor an email to an organization, impersonate a legitimate contact, and try to redirect payments or obtain sensitive information.
A compromised admin account can be even more damaging. It may allow attackers to reset passwords, access additional systems, export data, or weaken security controls. Once that happens, a single compromised identity can lead to a much larger incident.
Even ordinary employee accounts may connect to:
- Email and calendars.
- CRM and customer support tools.
- HR and payroll systems.
- Cloud storage.
- Internal chat and collaboration platforms.
- Shared credentials and password vaults.
- Developer or infrastructure tools.
Corporate account hijacking goes beyond just fraud. It’s an access control problem that can have organization-wide consequences.
Detection signals businesses should watch out for
Because account takeover often begins with valid credentials, detection depends on spotting irregular behavior.
- Unusual login times or locations: A login from an unfamiliar country, region, or time pattern can be suspicious, especially if it is followed by configuration changes.
- Unexpected password reset requests: Employees receiving reset emails they did not request may be seeing early signs of an attempted takeover.
- Unfamiliar devices or browsers: a login from a never-before-seen device is worth reviewing, particularly when paired with unusual app access or sharing behavior.
- 2FA prompts not initiated by the account owner: Unexpected 2FA approvals can signal that someone already has an account password and is trying to get through the second layer.
- Mailbox or forwarding rule changes: Attackers who compromise email accounts often create rules to hide messages, forward mail, or preserve access.
- Unusual activity in sensitive tools: A user suddenly accessing finance systems, admin dashboards, exports, or shared secrets in ways that don’t fit their normal responsibilities may indicate compromise.
- Suspicious changes in vaults or shared credentials: if passwords are modified, re-shared, or accessed in unusual ways, it may be a sign of account misuse rather than normal collaboration.
The business impact of account takeover
The reason account takeover fraud is so serious is that one compromised identity can suddenly create several kinds of damage. There is the immediate fraud risk. An attacker may impersonate an executive, employee, or vendor to request payment changes or confidential information.
There is also the data risk. A compromised account may expose contracts, customer data, internal files, or sensitive communications.
Then, there is the operational risk. Teams may have to lock accounts, rotate credentials, revoke access, review logs, verify communications, and check for lateral movement.
If the attacker reaches privileged systems, the incident can escalate far beyond one compromised account. They may be able to deploy ransomware, maintain access to critical systems, or enable wider compromise across the environment.
At that point, the issue is no longer simply securing a user’s identity. It can disrupt operations, delay recovery, and affect the organization’s ability to function normally, which is why account takeover must be accounted for in business continuity planning.
Your practical response plan for a suspected account takeover
Even with strong preventive controls in place, businesses still need to be ready to respond quickly when an account takeover is suspected. A fast, structured response can help contain the incident before it spreads to other systems or workflows.
- The first step is to contain the risk by temporarily disabling the affected account, revoking active sessions, and resetting credentials. Teams should then review recent login activity and any suspicious changes linked to the account. If the account has broader permissions or access to sensitive tools, the response should move even faster.
- From there, the focus should shift to scope. Businesses need to understand what the attacker may have accessed, changed, or used while inside the account, including email rules, connected apps, shared credentials, and signs of lateral movement.
- It is also important to contain any related exposure. A compromised identity may affect finance processes, vendor communications, internal tools, or customer data, so response should not stop at the account itself.
- Once the immediate risk is under control, the incident should be used to strengthen what failed, whether that means improving credential hygiene, tightening 2FA enforcement, or improving detection through activity logs and identity monitoring workflows. These tools help surface suspicious login patterns, such as unusual locations, repeated failed attempts, odd-hour access, or unexpected account changes, so security teams can investigate earlier.
Building a stronger security culture around account access
Account takeover thrives when access is treated as a convenience issue instead of a security discipline.
A stronger security culture means employees understand that credentials are not just personal logins. They are access keys to business systems, customer trust, and operational continuity. It also means organizations make the secure path the easy path by giving teams proper tools, clear policies, and centralized support.
That is where enterprise password managers, passkeys, dark web monitoring, stronger 2FA practices, and secure offboarding work together. These controls help reduce credential reuse, improve account hygiene, and limit how much damage one compromised account can do.
Detection belongs to the wider monitoring layer, but password managers can still support it by generating logs and reports that feed into investigation and alerting systems. Together, these controls make account takeover harder to execute and easier to contain.
How Proton Pass for Business reduces account takeover risk
Many account takeover incidents start with exposed, weak, or reused credentials, then escalate because employees don’t have a consistent way to generate strong passwords, store them securely, use 2FA reliably, or spot early signs of exposure. Proton Pass for Business reduces that risk by making stronger account practices easier to apply across teams, not just easier to recommend.
Stronger password hygiene at scale
A secure password manager supports strong password generation, autofill, secure storage, and secure sharing, which helps teams move away from reused passwords, browser sprawl, and informal credential handling.
This is essential for preventing account takeover because attackers often rely on password reuse and predictable login habits to turn one exposed credential into access across multiple services. Proton Pass also supports passkeys, which reduce reliance on passwords for supported services and offer phishing-resistant sign-in protection. It also offers a built-in 2FA authenticator and autofilling TOTP codes, which makes stronger login habits easier to use consistently.
Better visibility into exposed and risky credentials
Proton Pass includes Pass Monitor, which offers password health insights, dark web monitoring alerts for breached emails, and visibility into inactive 2FA. In practice, that helps organizations identify weak, reused, or already-exposed credentials before they are abused in credential stuffing or follow-on takeover attempts.
A business password manager is ideal for account takeover prevention. It helps team members safely store and manage credentials, as well as helping teams identify the ones most likely to create downstream risk.
More usable 2FA in day-to-day work
2FA helps make a stolen password less useful on its own, but adoption often breaks down when it feels inconvenient or fragmented. Proton Pass helps here by supporting a built-in 2FA authenticator and autofill for OTP codes, which makes stronger login habits easier to use consistently across supported accounts. That does not replace broader identity controls, but it does narrow one of the practical gaps attackers often exploit.
Admin control and security signals that support investigations
Proton Pass also contributes useful admin and security visibility through reporting, logs, and activity information. This helps organizations review credential-related activity, support internal investigations, and feed relevant signals into broader security workflows where needed.
How Proton Sentinel complements Proton Pass for Business
Proton Sentinel is an advanced account protection program available across eligible Proton plans that creates a stronger layer of protection for Proton Accounts themselves, including stricter challenges for suspicious login attempts, greater visibility into logins and account changes, and 24/7 escalation of suspicious events to security analysts.
That makes it relevant for protecting access to the Proton Account and, by extension, the sensitive data stored inside Proton services. But it should not be presented as if it detects suspicious logins across a company’s entire SaaS stack.
Proton Pass for Business helps reduce account takeover risk by improving password hygiene, making MFA easier to use, surfacing exposed or weak credentials earlier, and giving teams better control over how credentials are managed across the organization. Proton Pass for Business strengthens the credential practices that attackers most often exploit, while Proton Sentinel can add another layer of protection for the Proton account itself.
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