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Android SDK 4.0 and later offers packages to implement capabilities to establish network connections. For example, by using java.net
, javax.net
, android.net
or or org.apache.http
, a developer can create server sockets or HTTP connection. org.webkit
offers functions necessary to implement web browsing capabilities.
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Trusting All Certificates
- The developer implements the TrustManager interface so that it will trust all the server certificate (regardless of who signed it, what is the CN etc.)
Allowing All Hostnames
- The app does not verify if the certificate is issued for the URL the client is connecting to.
- When a client connects to example.com, it will accept a server certificate issued for some-other-domain.com.
Mixed-Mode / No SSL
- A developer mixes secure and insecure connections in the same app or does not use SSL at all.
On Android, using HttpURLConnection
is recommended for HTTP client implementation.
Noncompliant Code Example
The following code
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implements a custom MySSLSocketFactory
class that inherits javax.net.ssl.SSLContext
:
Code Block | ||
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privatepublic Stringclass filenameextends =SSLSocketFactory "myfile" private String string = "sensitive data such as credit card number" FileOutputStream fos = null; try { file file = new File(getExternalFilesDir(TARGET_TYPE), filename); fos = new FileOutputStream(file, false); fos.write(string.getBytes()); } catch (FileNotFoundException e) { // handle FileNotFoundException } catch (IOException e) { // handle IOException } finally { if (fos != null) { try { fos.close(); } catch (IOException e) { } } }{ SSLContext sslContext; public MySSLSocketFactory (KeyStore truststore) throws NoSuchAlgorithmException, KeyManagementException, KeyStoreException, UnrecoverableKeyException { super(truststore); this.sslContext = SSLContext.getInstance("TLS"); this.sslContext.init (null, new TrustManager[] {new X509TrustManager() { public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException { } public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException { } public X509Certificate[] getAcceptedIssuers() { return null; } }}, null); } public Socket createSocket() throws IOException { return this.sslContext.getSocketFactory().createSocket(); } public Socket createSocket(Socket socket, String host, int port, boolean autoClose) throws IOException , UnknownHostException { return this.sslContext.getSocketFactory().createSocket(socket, host, port, autoClose); } } <tt>checkClientTrusted()</tt> and <tt>checkServerTrusted()</tt> are overriden to make a blank implementation so that <tt>SSLSocketFactory</tt> does not verify SSL certificate. <tt>MySSLSocketFactory</tt> class is used to create an instance of <tt>HttpClient</tt> in other part of the application: public static HttpClient getNewHttpClient() { DefaultHttpClient v6; try { KeyStore v5 = KeyStore.getInstance(KeyStore.getDefaultType()); v5.load(null, null); MySSLSocketFactory mySSLScoket = new MySSLSocketFactory(v5); if(DefineRelease.sAllowAllSSL) { ((SSLSocketFactory)mySSLScoket).setHostnameVerifier(SSLSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER); } BasicHttpParams v2 = new BasicHttpParams(); HttpConnectionParams.setConnectionTimeout(((HttpParams)v2), 30000); HttpConnectionParams.setSoTimeout(((HttpParams)v2), 30000); HttpProtocolParams.setVersion(((HttpParams)v2), HttpVersion.HTTP_1_1); HttpProtocolParams.setContentCharset(((HttpParams)v2), "UTF-8"); SchemeRegistry v3 = new SchemeRegistry(); v3.register(new Scheme("http", PlainSocketFactory.getSocketFactory(), 80)); v3.register(new Scheme("https", ((SocketFactory)mySSLScoket), 443)); v6 = new DefaultHttpClient(new ThreadSafeClientConnManager(((HttpParams)v2), v3), ((HttpParams)v2)); } catch(Exception v1) { v6 = new DefaultHttpClient(); } return ((HttpClient)v6); } |
Proof of Concept
Typically, an application stores files in the directory as follows:
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[Android API 2013] | Class Environment |
[JSSEC 2013] | 4.6 Secure File Handling |