A breakup is a major upheaval — the kind that turns life upside down. The familiar order of things, where two people shared the same interests, moments, and often even the same physical space, collapses in an instant, leaving each of you in a world of your own.

Besides that, couples are connected not just in real life, but digitally too. Shared subscriptions, saved addresses and passwords, access to joint cloud storage — all of that used to be woven into your day-to-day life. Moving on emotionally can take a long time, sure, but there are steps you can take right now that will tighten up your security — even if they won’t help you get over your ex.

Here’s what you need to check after a breakup, which services to disconnect, and why you should do it even if the split was amicable.

Digital hygiene: your insurance policy

Cutting off your ex’s access to your online accounts isn’t paranoia — it’s looking out for your own security. A breakup doesn’t automatically sever your digital ties: any access you granted each other during the relationship stays active until someone manually shuts it down. Most of the time, nobody’s plotting to actually exploit it, yet it can still lead to anything from awkward moments to a genuine risk of being tracked.

Take Aleta Dignard-Fung, of Las Vegas, who told NPR that after breaking up with her boyfriend, it didn’t immediately occur to her that he still knew her Spotify password. One day, in the shower with music playing, she noticed her playlist suddenly switch. Her ex had logged in from another device and started playing his own chosen tracks. “It was just kind of like the Spotify wars, and we’d just spend like 10 minutes trying to override each other’s songs,” she admitted. But the fallout isn’t always this lighthearted.

Relationship coach Susan Winter shared a case from her own practice in that same interview. One of her clients simply couldn’t let go of his ex-girlfriend after their breakup. The two had shared an OpenTable account — the restaurant reservation service — and she’d never revoked his access. He started tracking her bookings: where she was going, what time, how many people. That’s how he kept tabs on whether someone new had entered her life.

These two stories, while showing very different behavior from the exes involved, both trace back to the same root cause: accounts that were never properly locked down. In the former case, it led to an awkward moment. In the latter, it led to anxiety and a real sense of being watched. To make sure neither scenario happens to you, it’s worth running through a quick checklist.

Terminate your partner’s sessions

In the settings for your social media, messaging apps, email, and other key services, pull up the list of active sessions and log out everything except your current devices.

Change your passwords

Update the passwords to any key accounts your partner might have known — say, if you used a meaningful date as your password. If you reused the same password across multiple services, change it everywhere. While you’re at it, review your security questions and your backup email or phone number for account recovery — neither should still be tied to your ex. To skip the hassle of memorizing new credentials while still leveling up your security, we recommend using a password manager — it’ll generate a unique, strong password for every account, and save and sync it across all your devices; the only thing you need to remember is a single main password.

Check two-factor authentication and trusted devices

Make sure verification codes only go to your own device. Remove your partner’s devices from your trusted list — you can do this in your Apple and Google account settings.

Split up your shared Apple/Google accounts

If you shared an Apple or Google account, sign out of that. Turn off Family Sharing, iCloud, and backups. Check your shared photo albums too — anything that lands there automatically is visible to your ex as well.

Review your subscriptions

If you shared subscriptions — streaming services, family plans, that kind of thing — cancel them or set up new ones and link your own card.

Check your bank cards

If your ex’s card is linked to a marketplace, delivery app, or rideshare service account you own, remove it from your saved payment methods. If your card is linked to their account and you no longer have access to it, the safest move is to just get your card reissued.

Revoke smart home access

Cut off your ex’s access to cameras, video doorbells, GPS trackers, and smart speakers. If the devices were on a shared account, change the password or move them over to your own personal account.

Review your privacy settings

Check the privacy settings across your accounts on various services and social media using our free online tool, Privacy Checker. It walks you through a privacy configuration tailored to your operating system, platform, and even your browser.

If you notice signs of stalking

Reach out to advocacy or legal aid organizations — they can help you map out the best course of action. It’s also worth leaning on family and close friends who can support you through a tough situation. On Android devices, you can use our security suite with the Who’s Spying on Me feature. It’s designed to help you detect tracking and stalking so you can take the right steps to protect yourself. The feature includes:

• Stalkerware Detection. Flags apps designed to secretly monitor your life and collect data you’d never want shared with anyone else.
• Device Scanner. Finds planted trackers that let someone follow your movements and always know where you are.
• Permissions Control. Shows which apps have access to permissions that could make it easier for someone to spy on you or compromise your privacy.

What can actually help — and what might make things worse — during this difficult time? Check out our other posts:

• Love, AI & robots
• What happens in the bedroom stays in the bedroom
• How chatting with a bot can lead to tragedy
• AI and the new reality of sextortion
• Digital detox: How to take a safe break from screens
• Subscription security: how to protect your account, your wallet… and your sanity

When targeting an organization to steal information, maintaining a low profile is critical for attackers. They typically aim for long-term persistence, which requires avoiding security alerts while preserving access in case they’re detected and the organization initiates incident response or routine password resets. Malware such as infostealers or ostensibly legitimate remote monitoring and management (RMM) tools fail the first requirement: their use triggers EDR and generates suspicious events in SIEM consoles. Relying on stolen credentials conflicts with the second requirement: the moment the security team suspects a compromise, passwords can be changed immediately — terminating access. If attackers attempt to steal browser cookies instead of passwords, they face a different challenge: many online services now correlate device characteristics with the expected session cookie and block access if the cookie is used on an unrecognized device. Furthermore, cookie theft protection mechanisms implemented in Chromium-based browsers (such as Chrome, Edge, and Opera) this year have made this approach significantly more difficult.

To address this persistence challenge, the ToddyCat APT — whose main game is spying — developed a novel technique. Kaspersky experts discovered this method during an incident investigation and named it Shadow Token via Remote Debug (STRD). This technique allows the attackers to establish reliable, persistent access to a victim’s mailbox and other resources in Google Workspace. With minor adjustments, the same approach could potentially be adapted to target other services that grant third-party application access via OAuth 2.0 authentication.

How an STRD attack works

First, the attackers must compromise the victim’s system with malware. In past campaigns, ToddyCat gained initial access to organizations by exploiting known vulnerabilities in server software and distributing malicious loaders via messaging apps. The specific employee targeted by the attackers might not notice the intrusion at all. This can occur, for example, if the adversary first obtains privileged administrative credentials and uses them to deploy the malware onto targeted machines remotely. Crucially, the deployment and execution of this malware mustn’t trigger immediate security alerts.

Once active, the malware executes an STRD attack, connecting the attackers’ remote service to the victim’s mailbox using the OAuth 2.0 protocol. This process requires no user interaction and shows no visible activity on the screen. To the cloud environment (Google Workspace, in the case at hand), the activity appears as if the user has legitimately authorized a third-party app for email access or data backup.

After that, the malware can terminate its operations and even delete itself from the system. The adversary retains direct access to the mailbox using the acquired OAuth token — and they need no connection to the victim’s endpoint or to the corporate network for that. Depending on the organization’s Google Workspace configuration, this access can persist for an extended period and survive subsequent password resets.

The core concept of Shadow Token via Remote Debug

At the heart of this attack is a connection to Google Workspace services via OAuth 2.0. This is a legitimate workflow used whenever a third-party application requests access to calendar data, emails, or Google Drive files. For example, to display calendar meetings in Zoom and automatically generate conference links, a user must authorize Zoom to access Google services. Similarly, configuring a third-party email client or calendar app requires granting permission. During this authorization process, the service requesting access opens a new browser window. In this window, Google Workspace first prompts the user to select the appropriate account. Once the account is chosen, the subsequent screen displays the specific permissions requested by the third-party app, allowing the user to either approve or deny access. For this scenario to proceed seamlessly, the user must already be authenticated to Google services in their browser — which is typically the case in organizations using Google Workspace. If the user isn’t authenticated, additional steps for entering credentials and completing multi-factor authentication are introduced into the sequence.

The ToddyCat hackers developed a malicious tool called Umbrij to facilitate a two-step covert authorization process when the user is already authenticated in Google. First, the malware identifies the browsers installed on the system, and locates the specific folder storing the user’s active profile for each. The attackers target Chrome and Edge, as these are the browsers most likely serving as the primary ones within the organization.

Next, Umbrij copies the entire user profile folder to a different directory on the machine. It then launches an instance of the browser, specifying the path to the duplicated profile via the command line. Because this duplicate profile contains the user’s session cookies, websites with saved credentials won’t prompt for re-authentication. Furthermore, since this occurs on the exact same computer where the primary browser is running, online services detect no anomalies. The browsing history for this newly launched instance is isolated within the new folder, keeping it hidden from the user’s main account activity.

Crucially, the browser is launched in a dedicated debugging mode typically reserved for web development. The browser window and user interface don’t appear on the screen at all (headless mode). Instead, the browser can be controlled through a debugging port using the DevTools protocol, allowing the malware to issue commands and read the state of the screen. To orchestrate these actions, Umbrij leverages Puppeteer, a legitimate automation library.

After verifying that the debugging browser instance has launched successfully, Umbrij opens a legitimate Google Workspace OAuth screen within it. The request sent to Google is engineered to bypass additional security checks while requesting maximum access privileges. For the application ID — the identity supposedly requesting these extensive permissions — the malware impersonates one of two legitimate tools: Google Workspace Migration for Microsoft Outlook (GWMMO), or Google Workspace Sync for Microsoft Outlook (GWSMO).

When Google opens the window within the headless browser, Umbrij uses debugging tools to programmatically click on the corporate account name and the confirmation buttons. As a result, Google generates an authorization code for the app. Umbrij extracts and saves this code, subsequently forwarding it to the attackers’ command-and-control server. Finally, operating entirely within their own infrastructure rather than on the victim’s computer, the attackers exchange this authorization code for an OAuth access token. This single token is all they need to maintain long-term unrestricted access to the mailbox.

How to protect against OAuth token theft

If a Google Workspace account is compromised, incident response measures must include the following steps after collecting the necessary logs and other forensic data for investigation:

• Resetting the affected user’s password
• Terminating all active web sessions for the user
• Revoking OAuth tokens and third-party app permissions
• Reviewing and removing access granted through legacy App Passwords

In addition, security and IT teams must systematically audit issued OAuth permissions, revoke unjustifiable access rights, and restrict capabilities that allow excessive or unauthorized permission grants. We covered this topic in detail in our article on blocking unwanted AI assistants.

How to prevent exploitation of Shadow Token via Remote Debug

While Kaspersky users are protected against the Umbrij tool, security teams should proactively implement policies that prevent standard users from launching browsers in debugging mode. This functionality is intended exclusively for website and web app developers. This restriction can be enforced through the DeveloperToolsAvailability group policy (available for both Chrome and Edge).

Additionally, configure monitoring within your SIEM/XDR to track the launch of browser instances with an active debugging port. This event serves as a strong indicator of this specific attack technique.