Critical Bugs Could Let Attackers Remotely Hack, Damage APC Smart UPS Devices

Périphériques APC Smart UPS News

Three high-impact security vulnerabilities have been disclosed in APC Smart-UPS devices that could be abused by remote adversaries as a physical weapon to access and control them in an unauthorized manner.

Collectively dubbed TLStorm, the flaws “allow for complete remote takeover of Smart-UPS devices and the ability to carry out extreme cyber-physical attacks,” Ben Seri and Barak Hadad, researchers from IoT security company Armis, said in a report published Tuesday.

Uninterruptible power supply (UPS) devices function as emergency backup power providers in mission-critical environments such as medical facilities, server rooms, and industrial systems. Most of the afflicted devices, totaling over 20 million, have been identified so far in healthcare, retail, industrial, and government sectors.

TLStorm is a series of three critical flaws. They can be activated via unauthenticated packets and do not require user interaction. Two of the problems involve a case of faulty TLS Handshake between the UPS, APC cloud –


  • CVE-2022-22805 (CVSS score: 9.0) – TLS buffer overflow
  • CVE-2022-22806 (CVSS score: 9.0) – TLS authentication bypass
  • CVE-2022-0715 (CVSS score: 8. 9) – Unsigned firmware upgrade that can be updated over the network

Successful exploitation of any of the flaws could result in remote code execution (RCE) attacks on vulnerable devices, which in turn could be weaponized to tamper with the operations of the UPS to physically damage the device or other assets connected to it.

“By using our RCE vulnerability we were able to bypass the software protection and let the current spike periods run over and over until the DC link capacitor heated up to ~150 degrees celsius (~300F), which caused the capacitor to burst and brick the UPS in a cloud of electrolyte gas, causing collateral damage to the device,” the researchers explained.

To make matters worse, the flaw in the firmware upgrade mechanism could be leveraged to plant a malicious update on UPS devices, enabling the attackers to establish persistence for extended periods of time and use the compromised host as a gateway for further attacks.

“Abusing flaws within firmware upgrade mechanisms has become a common practice of APTs,” researchers stated.

Following responsible disclosure to Schneider Electric on October 31, 2021, fixes have been released as part of Patch Tuesday updates on March 8, 2022. To reduce the chance of exploiting these vulnerabilities successfully, customers are advised to download the updated versions.

The researchers found that

“UPS appliances are, just like other digital infrastructure appliances in general, easy to forget about.” “Since these devices are connected to the same internal networks as the core business systems, exploitation attempts can have severe implications. “

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