1. Presented by Hussein Almulla
Why Eve And Mallory Love Android: An Analysis Of Android SSL (In)security
Presented by
Hussein Almulla

2. Outline Introduction Background Evaluating Android SSL Usage MITMA
Test Environment
Online Survey
Results of the Survey
Countermeasures
Conclusion

3. Purpose
In this paper, the authors investigated potential security threats that some Android apps could cause during process privacy data.
They also seek to better understand how these apps are using the SSL/TLS protocols to protect a transmitted data.
Lacking in usage SSL/TLS can be exploited to launch Man-in-the-Middle (MITM) attacks.
They choose Android because:
It is most used OS. It has 48% of market and has more than 400,000 apps
Google Play .Market are relatively open and unrestricted

4. What They Did
In order to discover apps’ vulnerabilities, they create Mallodroid.
Mallodroid perform code analysis to:
Analyze the networking API and validate HTTP(S) URLs
Check the validity of the SSL certificates
Identify apps that using SSL differently from default SSL.
Based on result, they select 100 apps to investigate SSL misuse.

5. SSL
It is cryptographic protocol that is used to protect network communication from eavesdropping and tempering.
To establish SSL, client must get the server’s public key that is included in server certificate. This certificate is signed by Certification Authority.
this certification is transferred when client connect to the server. After that client should validate it by checking:
Does the subject of the certificate match the destination selected by the client?
Is the signing CA a trusted?
Is the signature correct?
Is the certificate expire?
Check a revocation of certificates
The evaluation depending on this list.

6. Android & SSL
Because developer can customize their SSL usage, that can cause misuse.
Apps can use broken SSL to transmit information as following cases:
Trusting all Certificates: TrustManager interface can be implemented to trust all certificates does not matter who sign them.
Allowing all Hostnames: accept all certificates whether issue for the destination or not.
Trusting many CAs.
Mixed-Mode/No SSL.

7. MITM Attack
(MITMA), the attacker is in a position to intercept messages sent between communication partners.
The mixed-mode/no SSL case allows adversery to eavesdrop on non-protected communication.
SSL stripping is another method by which a MITMA can be launched against an SSL connection.
SSL stripping relies on redirected from non-SSL-protect site to protect one.
During this redirection adversary may be able to the secure link with unsecure one successfully if users does not notice that.

8. EVALUATING ANDROID SSL USAGE
They built MalloDroid to evaluate SSL usage. MalloDroid performs following analysis steps:
Permissions: checks which apps request the INTERNET or privacy-related permission,
Networking API Calls: analyzes the use of HTTP transport and Non-HTTP transport
HTTP vs HTTPS: checks the validity of URLs
HTTPS Available: tries to establish a secure connection to HTTP URLs found in apps.
Deployed Certificates: downloads and evaluates SSL certificates
SSL Validation: examines apps with respect to inadequate SSL validation such as accepts all certificates.

9. Permission The result of checking apps request
No. of apps
No. of total app
13,500
Internet permission
12,534
No. of apps that actually perform networking related API calls.
11,938
Internet and privacy permission.
6,907
They also found that 91.7% of apps that perform networking API calls are related to HTTP or HTTPS.
They focus on using HTTP or HTTPS to find which one is using.

10. MalloDroid extracted 254,022 URLs
HTTP vs. HTTPS
MalloDroid extracted 254,022 URLs
29,685 of the URLs (15.2%) pointing to 1,725 unique hosts (6.6%) are HTTPS URLs
6,214 of the apps contain HTTPS and HTTP URLs simultaneously
5,810 do not contain HTTPS URLs at all.
111 apps exclusively contained HTTPS URLs.

11. HTTP vs. HTTPS
Top 10 host based on occurrences

12. Deployed SSL Certificates
They downloaded 1,887 unique SSL certificates 162 failed the verification Android’s default verification strategies, include668 apps
42 of these certificates failed SSL verification because they were self- signed, 271 apps.
21 of these certificates were expired, 43 apps.

13. Custom SSL Validation Using MalloDroid, they found 1,074 apps
790 contain code that bypasses SSL verification by accepting all certificates.
284 contain code that accepts all hostnames for a certificate.
They found 86 custom trust managers and SSL socket factories in 878 apps.
22 classes implementing the TrustManager interface and 16 classes extending the SSLSocketFactory that accept all SSL certificates.
in 78 apps, MalloDroid found a SSLSocketFactory provided by a developer library that accepts all certificates.
313 apps contained calls to the NaiveTrustManager class.
In 90 apps, MalloDroid found the NonValidatingTrustManager

14. MITMA STUDY
The perform MITMA against 266 apps containing broken SSL or hostName verifies (Finance: 45, Social: 94, Communication: 49,Business: 60, Tools: 18).
They wanted to find what kind of information send through these broken SSL.

15. Test Environment They selected the top 100 apps for manual auditing.
These apps have between 39.5 and 185 million users.
For the manual app auditing, we used a Samsung Galaxy Nexus smartphone with Android 4.0.
They installed the potentially vulnerable apps on the phone.
Set up a WiFi access point with a MITM SSL proxy.
41 apps are vulnerable.
So it possible to gather bank account information, payment credentials, Facebook, and cloud storage credentials.

16. Trusting All Certificates
In this attack they gave their MITMA proxy a self-signed certificate for the attack.
21 apps among the 100 selected apps were vulnerable to this attack.
Installed base between 100,000 and half a million users.
The apps leaked information such as login credentials, webcam access or banking data.
24 of the 43 banks supported were not protected from our MITMA.
Windows Live Messenger service app also vulnerable for this attack.
has 10 to 50 million users it is in the top 20 apps for the communication.
Username and password are both sent via a broken SSL channel.

17. Allowing All Hostnames
They found 20 apps that accepted certificates irrespective of the subject name. if the app wants to connect to X.com, it would also accept a certificate issued to Y.com.
The apps leaked information such as credentials for different services, s, text messages, etc.
An anti-virus app updated its virus signatures file via a broken SSL connection.
No validation of the signature files.
First, they sent an empty signature database and it was accepted, so the anti-virus protection turning off without informing the user.
Second, they created a virus signature for the anti-virus app itself and sent it. This signature was accepted by the app. Then anti-virus recognized itself as a virus and delete itself.

18. SSL Stripping
SSL stripping can occur if a browsing session begins using HTTP and switches to HTTPS via a link or a redirect.
Two noteworthy examples vulnerable to this attack are a social networking app and an online services client app.

19. Lazy SSL Use Although the Android SDK does not support SSL pinning.
user, many Android apps focus on a limited number of hosts picked by the app developer
To implement SSL pinning, an app can use its own KeyStore of trusted root CA certificates or implement a TrustManager that only trusts specic public key fingerprints.
They investigate the usage of SSL pinning in 20 high apps against MITMA.
Only 2 apps make use of SSL pinning and were safe from this attack. Other apps trust all root CA signatures.

20. Lazy SSL Use

21. Missing Feedback
Android OS does not provide any visual feedback to the user whether or not communication channel is secure.
apps installed between million users
Handling registration and login via a secure SSL connection.
The default settings for sending and receiving are set to HTTP.
There was no indication that the s were not protected.
An instant messaging app installed100,000 to 500,000 users transfers login credentials via a non-SSL protected channel, without inform users.

22. Framework for graphical app builder
Missing Feedback
Framework for graphical app builder
allowing users to create apps for Android. Apps created with this framework can load code from remote servers.
Downloading remote code perform via plain HTTP.
Because downloaded code is not verified before execution, it is possible to inject and execute java code.
Also they found 53 apps were not vulnerable for MITMA but they did not give meaningful warning messages to the users who are under attack.

23. Limitation of the Analysis
The studied applications were selected depend on popularity.
They only checked 100 apps manually to detect vulnerability against MITMA.
They did not check the rest of apps that have unsafe SSL implementation.
Static code analysis might fail in some apps.
The applications that selected for manual audit were chosen base on popularity and handling sensitive data.

24. Online Survey
They made survey in find out whether users can evaluate the security connection or not
Used default Android browser as example to find out:
Users can distinguish a HTTPS connection from a regular HTTP connection .
How users perceives an SSL warning message.
accessed directly from an Android phone.
Half user get the survey via HTTPS and another half via HTTP.

25. Online Survey Users were asked about, 754 participants
Whether they had seen this warning before.
If they had completely read its text and
How much risk they felt.
47.5% of non-IT experts and 34.7% of participant with IT education though that they used a secure connection, but the survey was over HTTP.
In both groups, 22.4% were unsure about security of their connection.
58.9% of experts and 44.3% of non-experts correctly identified whether they were using a secure or insecure connection.
57.6% of non-IT experts and 52.3% of IT experts state that they had not seen such a certificate warning before
24.0% of participants read the warning, and 4.5% did not read it at all
They rated the risk of this warning with 2.86 from 5.

26. Limitation of Online Survey
They did not digitally sign the s.
The URL that sent with the survey was not linked to the university.
The s could have been spoofed.
Most of the participants who complete the survey were students.

27. Countermeasures OS Solutions : App Market Solutions:
that are integrated into the Android OS.
App Market Solutions:
that are integrated into app markets
Standalone Solution:
The MalloDroid App & Service

28. OS Solutions
This can be achieved by forcing developers to use the standard library implementations provided by Android's APIs.
HTTPS-Everywhere: integrated into the communication APIs. This would prevent most SSL stripping attacks.
Improved Permissions and Policies: apps indicate which type of connections is used INTERNET_SSL or INTERNET_PLAIN. In order to get users permission.
Visual Security Feedback: The operating system should provide visual feedback on whether or not apps are using secure channel.
MalloDroid Installation Protection: MalloDroid could be integrated into app installers to perform static code analysis at install time.

29. MalloDroid Solutions App Market Solutions :
MalloDroid could be integrated into app markets
Automated checking apps before add to the market.
And either reject apps from entering the market or warnings could be added to the app's description.
Standalone Solution: The MalloDroid App & Service
They offer MalloDroid tool. This allow users to perform checks on apps before they install them.
This solution does not require to modified a OS.

30. Conclusion They investigate SSL/TLS usage in Android.
They built MalloDroid that use for static code analysis in order to detect apps that use SSL/TLS incorrectly and vulnerable to MITM attacks.
They manually perform MITM attacks against 100 selected apps from that set.
They captured credentials for American Express, Paypal, Facebook, …
They did online survey with 754 participants to find out what users react about security warning.
They offer MalloDroid as a first countermeasure to identify vulnerable apps.

31. Thank you Question?