Portugal’s national intelligence service has warned that foreign state-backed hackers are targeting messaging accounts used by government officials, diplomats, and military personnel. The alert was issued by the Security Intelligence Service, known as SIS, which is responsible for domestic intelligence and national security in Portugal.
The agency said the activity is part of a cyberespionage campaign designed to gain access to accounts on WhatsApp and Signal used by individuals with access to sensitive information.
According to the SIS advisory, the attackers are not attempting to break the encryption used by the messaging platforms. Instead, they rely on social engineering techniques that persuade users to provide access to their accounts.
The intelligence service said the campaign targets individuals, including government officials, diplomats, military personnel, and members of civil society who may have access to confidential information in Portugal and allied countries.
SIS did not identify which country may be responsible for the activity. The agency described the operation as a global effort to compromise individual accounts and obtain information from private conversations and shared files.
The report states that attackers use phishing messages, impersonation attempts, and malicious links to trick victims into revealing credentials or verification codes. In some cases, the attackers pose as technical support or trusted contacts to make the messages appear legitimate.
The agency said the attacks focus on persuading users to perform actions that undermine the security of their own accounts. According to the advisory, this can include sharing login codes, scanning QR codes, or approving the connection of new devices to an account.
Once access is obtained, attackers can view private chats, read group conversations, and download shared files. SIS said the compromised accounts can also be used to send further phishing messages to the victim’s contacts.
The intelligence service also noted that artificial intelligence tools may be used to improve the effectiveness of impersonation attempts. According to the report, AI can help attackers generate convincing messages or mimic identities during communication attempts.
Authorities said the warning was issued to help potential targets recognize the tactics used in the campaign. SIS advised users to verify new contacts through separate communication channels and avoid sharing verification codes or login details.
The advisory follows similar warnings from intelligence agencies in other countries. Earlier this week, Dutch intelligence services reported that hackers linked to Russia had attempted to gain access to WhatsApp and Signal accounts used by officials, journalists, and military personnel through comparable methods.