Hacked Telegram, but I don’t know how it could have been

Understanding a Recent Telegram Account Breach: What You Need to Know

In today’s digital landscape, security breaches can happen even to users with minimal activity on certain platforms. Recently, a user shared their experience of having their Telegram account compromised unexpectedly, prompting questions about how such incidents occur and what precautions can be taken. Here, we analyze the situation, shed light on potential vulnerabilities, and provide guidance on safeguarding your online presence.

A User’s Experience: An Unexpected Security Incident

The individual in question reported that they do not actively use Telegram but had an account stored on their device. One day, they noticed a login activity from an unfamiliar account on their phone. The login was detected approximately 20 minutes prior, and upon checking, the user promptly responded by selecting the “No, it’s not me” option, which terminated the suspicious session.

To secure their account further, they deleted the Telegram account entirely, changed their associated phone number, and removed the app from all linked services, including email. Interestingly, immediately after denying access, they received an SMS message containing a verification code—raising questions about how the breach may have occurred.

Key Concerns and Clarifications

How could the account have been compromised?
The user is uncertain about the breach, especially since they did not notice any suspicious activity before. Possible explanations include:
Weak or reused passwords (if the Telegram account was linked to an email or password), though Telegram primarily uses phone number verification.
SIM swapping or phone number hijacking, where an attacker takes control of the victim’s phone number.
Malware or spyware on their device that captured login credentials or session tokens.
Exploitation of vulnerabilities in the Telegram app itself (rare, but possible if the app or device was compromised).
The SMS code received — was it a sign of intrusion?
The appearance of an SMS with a code suggests someone attempted to verify or access the account, possibly before the user responded to the login request. This indicates that an attacker may have tried to initiate a login, which was thwarted when the user denied it.
Could the account have been compromised via other linked services?
The user checked email logs and recent activity but found no suspicious activity. Nonetheless, it’s always advisable to review all linked accounts and check for any unauthorized access.