A serious vulnerability has been found in yet another computerized control system that runs some of the world's most critical infrastructure, this time in a product sold by a vendor known as the ABB Group.

According to researchers from C4 - a firm specializing in the security of so-called SCADA, or Supervisory Control And Data Acquisition, systems - ABB's Process Communication Unit (PCU) 400 suffers from a critical buffer overflow bug.

"The vulnerability was exploited by C4 to verify it can be used for arbitrary code execution by an unauthorized attacker," researcher Idan Ofrat wrote in this advisory published on Thursday. "In addition, an attacker can use his control over the FEP server to insert a generic electric grid malware...in order to cause harm to the grid."

The vulnerable software controls critical national infrastructure, including electrical grids. The vulnerability affects versions 4.4, 4.5, and 4.6, and possibly others, the C4 advisory warns.

ABB has issued a patch for the bug.

The advisory comes as concern mounts about the safety of software used to run gasoline refineries, manufacturing plants and other industrial facilities. In June, a now-patched vulnerability in CitectSCADA potentially exposed plants' critical operations to outsiders or disgruntled employees. Law makers on both sides of the Atlantic have warned that lax security may make critical infrastructure vulnerable to saboteurs or terrorists.

C4 is no stranger to security in SCADA systems. In January, it warned of vulnerabilities in two products made by Ge Fanuc. One of them resided in Ge Fanuc's Cimplicity product, and the other affected the company's Proficy Information Portal 2.6. Both appear to have have been patched. ®