Starbucks 2.6.1 Information Disclosure

`Title: [CVE-2014-0647] Insecure Data Storage of User Data Elements in Starbucks v2.6.1 iOS mobile application  
Published: January 13, 2014  
Reported to Vendor: December 2013 (no direct response)  
CVE Reference: CVE-2014-0647  
Credit: This issue was discovered by Daniel E. Wood  
http://www.linkedin.com/in/danielewood  
  
Product: Starbucks iOS mobile application  
Version: 2.6.1 (May 02, 2013)  
Vendor: Starbucks Coffee Company  
URL: https://itunes.apple.com/us/app/starbucks/id331177714  
  
Issue: Username, email address, and password elements are being stored in clear-text in the session.clslog crashlytics log file.  
Location: /Library/Caches/com.crashlytics.data/com.starbucks.mystarbucks/session.clslog  
  
Within session.clslog there are multiple instances of the storage of clear-text credentials that can be recovered and leveraged for unauthorized usage of a users account on the malicious users’ own device or online at https://www.starbucks.com/account/signin. It contains the HTML of the mobile application page that performs the account login or account reset. session.clslog also contains the OAuth token (signed with HMAC-SHA1) and OAuth signature for the users account/device to the Starbucks service.  
  
From session.clslog:  
<div class="block_login">  
<form action="/OAuth/sign-in" class="siren" id="accountForm" method="post">  
<fieldset class="login_position">  
<legend><span class="group-header">I have a Starbucks account.</span></legend>  
  
[...snip...]  
  
<li>  
<label for="Account_UserName" class="">Username <span class='req'>*</span></label>  
<span class="x">  
<input class="field text medium" id="Account_UserName" maxlength="200" name="Account.UserName" tabindex="0" type="text" value="CLEARTEXT" />  
</span>  
</li>  
<li>  
<label for="Account_PassWord" class="">Password <span class='req'>*</span></label>  
<span class="x">  
<input class="field text medium" id="Account_PassWord" maxlength="200" name="Account.PassWord" tabindex="0" type="password" value="CLEARTEXT" />  
</span>  
</li>  
  
43440 $ -[AccountManager forgotPasswordEmail:withUserName:] line 1609 $ BODY STRING:[ {"emailAddress":"CLEARTEXT","userName":"CLEARTEXT"} ]  
  
Note: All references of 'CLEARTEXT' above are the cleartext values of each referenced string.  
  
  
Mitigation:  
To prevent sensitive user data (credentials) from being recovered by a malicious user, output sanitization should be conducted to prevent these data elements from being stored in the crashlytics log files in clear-text, if at all.  
  
iOS Specific Best Practices (from OWASP Mobile Top 10 - M1 Insecure Data Storage):  
- Never store credentials on the phone file system. Force the user to authenticate using a standard web or API login scheme (over HTTPS) to the application upon each opening and ensure session timeouts are set at the bare minimum to meet the user experience requirements.  
- Where storage or caching of information is necessary consider using a standard iOS encryption library such as CommonCrypto  
- If the data is small, using the provided apple keychain API is recommended but, once a phone is jailbroken or exploited the keychain can be easily read. This is in addition to the threat of a bruteforce on the devices PIN, which as stated above is trivial in some cases.  
- For databases consider using SQLcipher for Sqlite data encryption  
- For items stored in the keychain leverage the most secure API designation, kSecAttrAccessibleWhenUnlocked (now the default in iOS 5) and for enterprise managed mobile devices ensure a strong PIN is forced, alphanumeric, larger than 4 characters.  
- For larger or more general types of consumer-grade data, Apple’s File Protection mechanism can safely be used (see NSData Class Reference for protection options).  
- Avoid using NSUserDefaults to store senstitve pieces of information as it stores data in plist files.  
- Be aware that all data/entities using NSManagedObects will be stored in an unencrypted database file.  
  
References:  
http://try.crashlytics.com/security/  
https://developer.apple.com/library/mac/documentation/Security/Conceptual/SecureCodingGuide/SecurityDevelopmentChecklists/SecurityDevelopmentChecklists.html#//apple_ref/doc/uid/TP40002415-CH1-SW1  
https://www.owasp.org/index.php/IOS_Developer_Cheat_Sheet#Insecure_Data_Storage_.28M1.29  
  
`