Protokollnedgraderingsattacker

Protokollnedgraderingsattacker, often referred to as protocol downgrade attacks, are a type of cybersecurity exploit where an attacker manipulates a communication protocol to force it to revert to a less secure version. This is typically done to circumvent security features present in the more secure, current version of the protocol.

These attacks exploit the negotiation process that occurs when two systems establish a communication channel. During this handshake, clients and servers often agree on the specific version of a protocol to use. An attacker positioned as a man-in-the-middle can intercept this negotiation and trick one or both parties into selecting an older, weaker protocol. For example, an attacker might force a web browser to use an outdated HTTP version instead of the more secure HTTPS.

The consequence of a successful protocol downgrade attack is that the communication then operates under the weaker security constraints of the older protocol. This can expose sensitive data to interception or modification, enable eavesdropping, or allow the attacker to inject malicious content into the communication stream. Many security protocols, such as TLS/SSL, have mechanisms designed to prevent such downgrades, but vulnerabilities can still exist in their implementation or in the way clients and servers handle protocol negotiation. Defense against these attacks involves robust implementation of security protocols, proper server configuration to disable support for weak protocol versions, and client-side security measures.