Instances from Programs must use the class javax.net.ssl.SSLSocket
should be created instead of normal Sockets when transferring objects over communication channels. SSLSockets
provide a layer of class rather than the java.net.Socket
class when transferring sensitive data over insecure communication channels. The class SSLSocket
provides security protocols such as SSL or TLSSecure Sockets Layer/Transport Layer Security (SSL/TLS) to ensure that the channel is not vulnerable to eavesdropping and malicious tampering.
The principal protections included in SSLSockets
SSLSocket
that are not provided by the Socket
class are : Java [API 2014]:
- Integrity Protection. : SSL protects against modification of messages by an active wiretapper.
- Authentication. : In most modes, SSL provides peer authentication. Servers are usually authenticated, and clients may be authenticated as requested by servers.
- Confidentiality (Privacy Protectionprivacy protection). : In most modes, SSL encrypts data being sent between client and server. This protects the confidentiality of data , so that passive wiretappers won't see sensitive data such as financial information or personal information of many kinds.
It is also important to use SSL for secure remote method invocation (RMI) communications because RMI depends on object serialization, and serialized data must be safeguarded in transit. Gong, Ellison, and Dageforde [Gong 2003] describe how to secure RMI communications using SSLSocket
.
Note that this rule lacks any assumptions about the integrity of the data being sent down a socket. For information about ensuring data integrity, see SER02-J. Sign then seal objects before sending them outside a trust boundary.
Noncompliant Code Example
This noncompliant code example shows the use of regular sockets for a server application that does not fails to protect sensitive information in transit. Te The insecure code for the corresponding client application follows the server's code.
Code Block | ||
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| ||
import java.net.ServerSocket; import java.net.Socket; import java.io.*; public // Exception handling has been omitted for the sake of brevity class EchoServer { public static void main(String[] args) throws IOException { ServerSocket serverSocket = null; try { ServerSocket serverSocket = new ServerSocket(100079999); Socket socket = serverSocket.accept(); PrintWriter out = new PrintWriter( socket.getOutputStream(), true); BufferedReader in = new BufferedReader( new InputStreamReader( socket.getInputStream())); String inputLine; while ((inputLine = in.readLine()) != null) { System.out.println (inputLine); out.println(inputLine); } } finally { if out.close(); (serverSocket != null) { in.close(); try { socket serverSocket.close(); } } catch (ExceptionIOException ex) { /*/ Handle exception*/ error } } } } {code:bgColor=#FFCCCC} import java.io.*; import java.net.*; public class EchoClient { public static void main(String[] args) throws UnknownHostException, IOException { Socket socket = null; try { Socket socket = new Socket("localhost", 9999); PrintWriter out = new PrintWriter(socket.getOutputStream(), true); BufferedReader in = new BufferedReader( new InputStreamReader(socket.getInputStream())); BufferedReader stdIn = new BufferedReader( new InputStreamReader(System.in)); String userInput; while ((userInput = stdIn.readLine()) != null) { out.println(userInput); System.out.println(in.readLine()); } } out.close();finally { if in.close();(socket != null) { stdIn.close(); try { socket.close(); } } catch (ExceptionIOException ex) { //* Handle exception*/ error } } } } } |
...
Note that the sockets are properly closed in accordance with ERR05-J. Do not let checked exceptions escape from a finally block.
Compliant Solution
This compliant solution makes use of SSLSockets
uses SSLSocket
to protect packets using the SSL and /TLS security protocols.:
Code Block | ||
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| ||
import javax.net.ssl.SSLServerSocket; import javax.net.ssl.SSLServerSocketFactory; import javax.net.ssl.SSLSocket; import java.io.*; public // Exception handling has been omitted for the sake of brevity class EchoServer { public static void main(String[] args) throws IOException { SSLServerSocket sslServerSocket = null; try { SSLServerSocketFactory sslserversocketfactorysslServerSocketFactory = (SSLServerSocketFactory) SSLServerSocketFactory.getDefault(); SSLServerSocketsslServerSocket sslserversocket = (SSLServerSocket) sslserversocketfactory.sslServerSocketFactory. createServerSocket(9999); SSLSocket sslsocketsslSocket = (SSLSocket) sslserversocketsslServerSocket.accept(); PrintWriter out = new PrintWriter( sslsocketsslSocket.getOutputStream(),true); BufferedReader in = new BufferedReader(new InputStreamReader( sslsocket.getInputStream())); new InputStreamReader(sslSocket.getInputStream())); String inputLine; while ((inputLine = in.readLine()) != null) { System.out.println (inputLine); out.println(inputLine); } } finally { out.close(); if (sslServerSocket != null) { in.close(); try { sslsocket sslServerSocket.close(); } } catch (ExceptionIOException ex) { /*/ Handle exception*/ error } } } import javax.net.ssl.SSLSocket; import javax.net.ssl.SSLSocketFactory; import java.io.*; public } } class EchoClient { public static void main(String[] args) throws IOException { SSLSocket sslSocket = null; try { SSLSocketFactory sslsocketfactorysslSocketFactory = (SSLSocketFactory) SSLSocketFactory.getDefault(); sslSocket SSLSocket sslsocket == (SSLSocket) sslsocketfactorysslSocketFactory.createSocket("localhost", 9999); PrintWriter out = new PrintWriter(sslsocketsslSocket.getOutputStream(), true); BufferedReader in = new BufferedReader( new InputStreamReader(sslsocketsslSocket.getInputStream())); BufferedReader stdIn = new BufferedReader(new InputStreamReader(System.in)); new InputStreamReader(System.in)); String userInput; while ((userInput = stdIn.readLine()) != null) { out.println(userInput); System.out.println(in.readLine()); } } out.close(); finally { if in.close(); (sslSocket != null) { stdIn.close(); try { sslsocket sslSocket.close(); } } catch (ExceptionIOException ex) { /*Handle exception*/ / Handle error } } } } } |
Note Programs that a program that makes use of SSLSockets
will hang if it tries use SSLSocket
will block indefinitely if they attempt to connect to a port that is not using SSL and. Similarly, similarly, a program that does not use SSLSockets
SSLSocket
will hang block when trying attempting to establish a connection through a port that uses SSL.
...
does use SSL.
Note that SSLSocket
does not validate host names, so providing an arbitrary host name to an SSLSocket
is still vulnerable to a man-in-the-middle attack. Host names should be validated separately. The HttpsURLConnection
class validates host names and is a suitable solution for secure web sockets.
Exceptions
MSC00-J-EX0: Because of the mechanisms that SSLSocket
provides to ensure the secure transfer of packets, significant performance overhead may result. Regular sockets are sufficient under the following circumstances:
- The data being sent over the socket is not sensitive.
- The data is sensitive but properly encrypted (see SER02-J. Sign then seal objects before sending them outside a trust boundary for more information).
- The network path of the socket never crosses a trust boundary. This could happen when, for example, the two endpoints of the socket are within the same local network and the entire network is trusted.
Risk Assessment
Use of plain sockets fails to provide any guarantee of the confidentiality and integrity of data transmitted over those sockets.
Rule | Severity | Likelihood | Remediation Cost | Priority | Level |
---|
MSC00-J |
Medium |
Likely |
High | P6 | L2 |
Exceptions
SEC36-EX1: Because of all the mechanisms that SSLSockets
provide to ensure the secure transfer of packets, significant performance overhead can be incurred. If no sensitive information is being transmitted, or the channel used is not prone to attacks, the implementation of regular Sockets
is sufficient.
References
Automated Detection
The general case of automated detection appears to be infeasible because determining which specific data may be passed through the socket is not statically computable. An approach that introduces a custom API for passing sensitive data via secure sockets may be feasible. User tagging of sensitive data is a necessary requirement for such an approach.
Tool | Version | Checker | Description | ||||||
---|---|---|---|---|---|---|---|---|---|
Parasoft Jtest |
| SECURITY.WSC.USC | Use the SSL-enabled version of classes when possible |
Related Guidelines
Bibliography
[API 2014] | |
Section 11.3.3, "Securing RMI Communications" | |
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