Pierluigi Paganini
June 30, 2024
TeamViewer discovered that a threat actor has breached its corporate network and some reports attribute the intrusion to the Russia-linked APT group APT29 (aka SVR group, BlueBravo, Cozy Bear, Nobelium, Midnight Blizzard, and The Dukes).
The unauthorized access to the IT infrastructure of the company occurred on June 26, threat actors used the credentials of a standard employee account within its IT environment.
Upon detecting the suspicious activity by this account, the company immediately started the incident response measures.
“A comprehensive taskforce consisting of TeamViewer’s security team together with globally leading cyber security experts has worked 24/7 on investigating the incident with all means available. We are in constant exchange with additional threat intelligence providers and relevant authorities to inform the investigation.” reads the statement published by the company.
“Current findings of the investigation point to an attack on Wednesday, June 26, tied to credentials of a standard employee account within our Corporate IT environment. Based on continuous security monitoring, our teams identified suspicious behavior of this account and immediately put incident response measures into action. Together with our external incident response support, we currently attribute this activity to the threat actor known as APT29 / Midnight Blizzard. Based on current findings of the investigation, the attack was contained within the Corporate IT environment and there is no evidence that the threat actor gained access to our product environment or customer data.”
An update published by TeamViewer states that findings confirmed that the attack on its infrastructure was limited to its internal corporate IT environment and did not affect the product environment, connectivity platform, or any customer data.
The popular Ars Technica reporter Dan Goodin reported that an alert issued by security firm NCC Group reports a “significant compromise of the TeamViewer remote access and support platform by an APT group.”
In May 2019, the German newspaper Der Spiegel revealed that the German software company behind TeamViewer was compromised in 2016 by Chinese hackers.
According to the media outlet, Chinese state-sponsored hackers used the Winnti trojan malware to infect the systems of the Company.
The Winnti group was first spotted by Kaspersky in 2013, according to the researchers, the nation-state actor has been active since at least 2007.
The gang is financially-motivated and was mostly involved in cyber espionage campaigns. The hackers were known for targeting companies in the online gaming industry, the majority of the victims are located in Southeast Asia.
The Winnti cyberespionage group is known for its ability in targeting supply chains of legitimate software to spread malware.
According to the company, it was targeted by the hackers in autumn 2016, when its experts detected suspicious activities were quickly blocked them to prevent major damages.
TeamViewer spokesperson revealed that the company investigated the attempts of intrusion, but did not find any evidence of exposure for customer data and sensitive data.
Der Spiegel pointed out that TeamViewer did not disclose the security breach to the public.
“In autumn 2016, TeamViewer was target of a cyber-attack. Our systems detected the suspicious activities in time to prevent any major damage. An expert team of internal and external cyber security researchers, working together closely with the responsible authorities, successfully fended off the attack and with all available means of IT forensics found no evidence that customer data or other sensitive information had been stolen, that customer computer systems had been infected or that the TeamViewer source code had been manipulated, stolen or misused in any other way.” said company spokesman.
“Out of an abundance of caution, TeamViewer conducted a comprehensive audit of its security architecture and IT infrastructure subsequently and further strengthened it with appropriate measures.”
At the time the company published a statement to exclude it was breached by hackers:
“Göppingen/Germany, May 23, 2016. A recent article warns, “TeamViewer users have had their bank accounts emptied by hackers gaining full-system access”. TeamViewer is appalled by any criminal activity; however, the source of the problem, according to our research, is careless use, not a potential security breach on TeamViewer’s side.” wrote the company.
Only in 2019, the company admitted it was breached in 2016.
Follow me on Twitter: @securityaffairs and Facebook and Mastodon
(SecurityAffairs – hacking, APT)
Security / September 16, 2025
