Hidden Backdoor in CCleaner Security App Has Infected 2.3 Million People

Hidden Backdoor in CCleaner Security App Has Infected 2.3 Million People

Hackers have hidden a backdoor in a security application called CCleaner. So far it has 2 billion downloads and has infected 2.3 million people and counting.

Security researchers have discovered cyber criminals have installed a backdoor in a security application for PCs. Users of the Avast-owned CCleaners for Windows have been advised to update their software immediately.

Researchers at Cisco Talos discovered the threat on Sept. 13 after CCleaner 5.33 caused their systems to flag malicious activity. The company warned that the hack could be comparable to the NotPetya ransomware outbreak, which spread after a Ukrainian accounting app was infected.

The hacked application allows for download of further malware, such as ransomware or keyloggers, and there are fears that virtually billions could be impacted. The security app has 2 billion downloads and claims to be getting five million extra a week, making the threat even more severe.

The backdoor installed in the application would send encrypted information about the infected computer - the name of the computer, installed software and running processes - back to the hacker's server. The hackers also used what is known as a domain generation algorithm (DGA) whenever the criminal's server went down, the DGA could create new domains to receive and send stolen data. Researchers have noted that the use of a DGA shows that these hackers are very sophisticated.

Further investigation found that the CCleaner download server was hosting the backdoored app as far back as Sept. 11 and the affected version had been released on August 15. Which means for weeks the malware was spreading inside a supposedly-legitimate security software.

On Sept. 12, CCleaner released an untained version of the software, version 5.34.

Featured

  • 2025 Gun Violence Statistics Show Signs of Progress

    Omnilert, a national leader in AI-powered safety and emergency communications, has released its 2025 Gun Violence Statistics, along with a new interactive infographic examining national and school-related gun violence trends. In 2025, the U.S. recorded 38,762 gun-violence deaths, highlighting the continued importance of prevention, early detection, and coordinated response. Read Now

  • Big Brand Tire & Service Rolls Out Interface Virtual Perimeter Guard

    Interface Systems, a managed service provider delivering remote video monitoring, commercial security systems, business intelligence, and network services for multi-location enterprises, today announced that Big Brand Tire & Service, one of the nation’s fastest-growing independent tire and automotive service providers, has eliminated costly overnight break-ins and significantly reduced trespassing and vandalism at a high-risk location. The company achieved these results by deploying Interface Virtual Perimeter Guard, an AI-powered perimeter security solution designed to deter incidents before they occur. Read Now

  • The Evolution of ID Card Printing: Customer Challenges and Solutions

    The landscape of ID card printing is evolving to meet changing customer needs, transitioning from slow, manual processes to smart, on-demand printing solutions that address increasingly complex enrollment workflows. Read Now

  • TSA Awards Rohde & Schwarz Contract for Advanced Airport Screening Ahead of Soccer World Cup 2026

    Rohde & Schwarz, a provider of AI-based millimeter wave screening technology, announced today it has won a multi-million dollar award from TSA to supply its QPS201 AIT security scanners to passenger security screening checkpoints at selected Soccer World Cup 2026 host city airports. Read Now

  • Brivo, Eagle Eye Networks Merge

    Dean Drako, Chairman of Brivo, the leading global provider of cloud-native access control and smart space technologies, and Founder of Eagle Eye Networks, the global leader in cloud AI video surveillance, today announced the two companies will merge, creating the world’s largest AI cloud-native physical security company. The merged company will operate under the Brivo name and deliver a truly unified cloud-native security platform. Read Now

New Products

  • AC Nio

    AC Nio

    Aiphone, a leading international manufacturer of intercom, access control, and emergency communication products, has introduced the AC Nio, its access control management software, an important addition to its new line of access control solutions.

  • Camden CV-7600 High Security Card Readers

    Camden CV-7600 High Security Card Readers

    Camden Door Controls has relaunched its CV-7600 card readers in response to growing market demand for a more secure alternative to standard proximity credentials that can be easily cloned. CV-7600 readers support MIFARE DESFire EV1 & EV2 encryption technology credentials, making them virtually clone-proof and highly secure.

  • Camden CM-221 Series Switches

    Camden CM-221 Series Switches

    Camden Door Controls is pleased to announce that, in response to soaring customer demand, it has expanded its range of ValueWave™ no-touch switches to include a narrow (slimline) version with manual override. This override button is designed to provide additional assurance that the request to exit switch will open a door, even if the no-touch sensor fails to operate. This new slimline switch also features a heavy gauge stainless steel faceplate, a red/green illuminated light ring, and is IP65 rated, making it ideal for indoor or outdoor use as part of an automatic door or access control system. ValueWave™ no-touch switches are designed for easy installation and trouble-free service in high traffic applications. In addition to this narrow version, the CM-221 & CM-222 Series switches are available in a range of other models with single and double gang heavy-gauge stainless steel faceplates and include illuminated light rings.