What are SSL and TLS inspection rules? How does it ensure data integrity during transmission over the Internet?
Overview of SSL and TLS Inspection Rules
SSL/TLS Inspection Rules are a set of IDS/IPS rules that inspect traffic. Then it verifies the integrity of data transmitted using SSL (Secure Sockets Layer) or TLS (Transport Layer Security). SSL is a commonly-used protocol for encrypting Internet communications.
On the other hand, TLS is the successor to SSL, with a larger list of cipher suites, which are the methods used for encryption. SSL/TLS Inspection Rules are ruled that use the SSL and TLS protocol inspection engine. The SSL/TLS Inspection Engine decrypts the network traffic and re-encrypts it with a chosen cipher suite, and compares the source data against the data received.
TLS connections use a client-server model as well. In this model, the server authenticates itself to the client. Then both sides negotiate an encryption method before exchanging application data.
What is SSL Inspection?
SSL-enabled applications transmit private user information in plaintext over a public network such as the Internet. This poses a significant security threat. Because it allows attackers to easily intercept data in transit by simply sniffing the network traffic.
The attacker can then use this sensitive information for various malicious purposes such as identity theft and financial fraud. So, the SSL inspection feature provides an additional layer of security for Internet users. This is done by decrypting and inspecting encrypted traffic for intrusion detection purposes.
This feature enables administrators to perform deep packet inspection and content filtering. So, this is on HTTP (Hypertext Transfer Protocol), FTP (File Transfer Protocol), Telnet, and other applications that rely on SSL protocol. Also, for secure communication over HTTP/HTTPS (Hypertext Transfer Protocol Secure).
The administrator can also perform content filtering on any other application using this protocol as well. These are such as IMAP (Internet Message Access Protocol), POP3 (Post Office Protocol 3), or SMTP (Simple Mail Transfer Protocol). So, without any need for developers to make any changes to their applications or code.
This makes it easier to scale security across a large number of applications and to maintain tight security for legacy applications. So, without the need for any changes or updates. Also, the SSL Inspection feature is available on the Cisco Adaptive Security Appliance (ASA) 5500 series adaptive security appliances.
Basic SSL/TLS Inspection Process
During the SSL/TLS handshaking process, the client sends a ClientHello message to the server that contains information about the client’s capabilities. This can include information about what encryption algorithms are supported by the client. Also, the server responds with its ServerHello message that contains its capabilities.
This includes a random number that will be used later in the authentication process. After this initial exchange of messages, the client and server negotiate a cipher suite to use for the encryption and decryption of their communication. If a vulnerability exists in some cipher suites, it can be used by an attacker to decrypt sensitive information during transmission over the public network.
Unless the SSL inspection feature is enabled on the device to inspect encrypted traffic. So, the SSL inspection feature enables administrators to configure rules that inspect data packets for any suspicious activities. This includes certain patterns or anomalies that might not be evident from looking at plaintext traffic.