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authorBoris Wachtmeister <boris-code@gmx.com>2015-03-07 15:36:31 +0100
committerBoris Wachtmeister <boris-code@gmx.com>2015-03-07 15:48:29 +0100
commit67f8ed44bd7241556a7cb1eb2aee2dda4cbbbf4e (patch)
tree6cf5c5c72c7fb8ae4c892572f6bd9f8c4f141062 /src/main/java/eu
parentcbca92d2099a9b3096b7ed6fbe0e5e8758f746fc (diff)
disable all really weak cipher suites
With #959 all ciphers of the platform were enabled, but this also includes several suites that are considered as very weak, even down to NULL- and anon-ciphers which disable completely disable encryption and/or authentication. Especially the anon-ciphers could be easily used for a mitm-attack. To remove all weak ciphers a blacklist with patterns of cipher-names was added to Config.java. The blacklist is based on the "mandatory discards" that Mozilla suggests to not use for TLS-servers because they are weak or known to be broken. https://wiki.mozilla.org/Security/Server_Side_TLS#Mandatory_discards
Diffstat (limited to 'src/main/java/eu')
-rw-r--r--src/main/java/eu/siacs/conversations/Config.java9
-rw-r--r--src/main/java/eu/siacs/conversations/utils/CryptoHelper.java16
2 files changed, 25 insertions, 0 deletions
diff --git a/src/main/java/eu/siacs/conversations/Config.java b/src/main/java/eu/siacs/conversations/Config.java
index 2b9cee9f..f38bcbfc 100644
--- a/src/main/java/eu/siacs/conversations/Config.java
+++ b/src/main/java/eu/siacs/conversations/Config.java
@@ -64,6 +64,15 @@ public final class Config {
"TLS_RSA_WITH_AES_256_CBC_SHA",
};
+ public static final String WEAK_CIPHER_PATTERNS[] = {
+ "_NULL_",
+ "_EXPORT_",
+ "_anon_",
+ "_RC4_",
+ "_DES_",
+ "_MD5",
+ };
+
private Config() {
}
diff --git a/src/main/java/eu/siacs/conversations/utils/CryptoHelper.java b/src/main/java/eu/siacs/conversations/utils/CryptoHelper.java
index 31fe2c11..eb7e2c3c 100644
--- a/src/main/java/eu/siacs/conversations/utils/CryptoHelper.java
+++ b/src/main/java/eu/siacs/conversations/utils/CryptoHelper.java
@@ -4,6 +4,7 @@ import java.security.SecureRandom;
import java.text.Normalizer;
import java.util.Arrays;
import java.util.Collection;
+import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
@@ -103,6 +104,21 @@ public final class CryptoHelper {
final List<String> platformCiphers = Arrays.asList(platformSupportedCipherSuites);
cipherSuites.retainAll(platformCiphers);
cipherSuites.addAll(platformCiphers);
+ filterWeakCipherSuites(cipherSuites);
return cipherSuites.toArray(new String[cipherSuites.size()]);
}
+
+ private static void filterWeakCipherSuites(final Collection<String> cipherSuites) {
+ final Iterator<String> it = cipherSuites.iterator();
+ while (it.hasNext()) {
+ String cipherName = it.next();
+ // remove all ciphers with no or very weak encryption or no authentication
+ for (String weakCipherPattern : Config.WEAK_CIPHER_PATTERNS) {
+ if (cipherName.contains(weakCipherPattern)) {
+ it.remove();
+ break;
+ }
+ }
+ }
+ }
}