Experts in system audits mention that two major PGP project contributors have been victims of multiple attacks by unidentified hackers that have managed to infect the certificates used by the SKS key server network.
PGP is a variant of encryption software used to ensure email communication between intelligence agencies. Robert Hansen and Saniel Kahn, two of OpenPGP’s lead developers, fell victim to a recent cyberattack sending spam to their public cryptographic identities.
The developers claim that a threat actor infected their certificates. This means that the legitimate PGP cryptographic identity cannot be authenticated correctly. “The hacker exploited a flaw in the OpenPGP protocol to poison our certificates. Anyone trying to import the affected certificates could compromise their IT infrastructure and that of their customers,” the system audits experts said.
“The poisoned certificates are already on the SKS key server network”, the developers mention. In addition, specialists believe that the low complexity of the attack could help its mass exploitation.
Experts in system audits consider it unlikely that this risk can be mitigated in the short term. The only alternative to mitigate risk for now is to stop retrieving certificates and other network data from the SKS key server.
The key server is a central component of PGP and user authentication of this protocol. Server design elements have worked correctly since its inception in the 1990s, although there are design flaws and potential attack vectors known for years.
“We knew about the possibility of this attack for at least ten years, today it has come to fruition and the outlook looks unoptimistic,” the developers say. Due to the read-only design of the key server certificate spam is only one of the multiple possible attack vectors against this project.
According to the experts of the International Institute of Cyber Security (IICS) there are severe technical problems that make it impossible for the key server to be protected against this attack; in other words, this code is so complex that it is not possible to fix these vulnerabilities with update patches, but a full system correction is required.