Lessons Learned From the Yahoo! Hack

Lessons Learned From the Yahoo! Hack

Amichai Shulman, CTO

© 2013 Imperva, Inc. All rights reserved.

Agenda

 Finding the vulnerable Yahoo! app
+ A true cyber detective story
 Yahoo! hack technical analysis
+ SQL Injection
+ Error based SQL Injection
 The greater lesson
+ 3rd party code security
 Summary and Conclusions

2 © 2013 Imperva, Inc. All rights reserved.

Amichai Shulman – CTO Imperva

 Speaker at Industry Events
+ RSA, Sybase Techwave, Info Security UK, Black Hat
 Lecturer on Info Security
+ Technion - Israel Institute of Technology
 Former security consultant to banks & financial
services firms
 Leads the Application Defense Center (ADC)
+ Discovered over 20 commercial application vulnerabilities
– Credited by Oracle, MS-SQL, IBM and others

Amichai Shulman one of InfoWorld’s “Top 25 CTOs”


Cyber Detective Story


Breaking News – Yahoo! Has been Hacked


Gathering Evidence

 Hacker released a redacted screenshot of the allegedly
hacked Yahoo! app


Forensics – Turning Evidence into Insights (1)

 Host name from address bar:
+ Ends in “yle.yahoo.net”, (not “yahoo.com”)
+ It has a relatively long host name


Forensics – Turning Evidence into Insights (2)

 Error message
+ The application is powered by ASP.NET
– Most Yahoo! Applications are PHP based
+ Application source file resides on C:webcorp[blackened by
hacker]pYahooV2app_code

Identifying the Vulnerable Yahoo! App (1)

+ It has a relatively long host name.



+ It has a relatively long host name.



 Error message
+ The application is powered by ASP.NET (not PHP like most
Yahoo! Applications)

Yahoo! Hack Technical Analysis
Error Based SQL Injection


Data Extraction Techniques by Hackers: 2005-2011

Other
17%

SQL Injection
83%

Total = 315,424,147 records
(856 breaches)

Source: Privacy Rights Clearinghouse


SQL Injection Means Business, Literally


SQL Injection: Technical Impact

Retrieve sensitive data
from the organization
Steal the site’s
administrator password
Lead to the downloading
of malware

Still A Very Relevant Attack

On average, we have identified 53 SQLi
attacks per hour and 1,093 attacks per day.


SQL Injections By the Hour – Highly Automated


Main Automated Attack Tools

SQLmap
Havij

Yahoo! Hack – MSSQL Injection with Conversion
Errors

 Attack vector:
+ ' and 1 = convert (int,(select top 1 table_name from x).

 The server tries to convert the additional data (in this
case the table name) to integer
 Character strings cannot be converted into integer, thus
an error is triggered
 If a system is not hardened, the error message is visible
to the attacker, revealing the data


MSSQL Injection with Conversion Errors

 No need to be a hacker to exploit
 Even script kiddies can do it with automated exploit tools
+ Havij


From SQL Injection to Command Execution

 In case of SQL injection in MSSQL DB, attacker can
leverage it to run arbitrary commands using the
“XP_CMDSHELL” system stored procedure
 Supported by exploit tools


3rd Party Code Security


Vulnerable Application is a 3rd Party Application

 “The leading astrology portal in India… formed co-
branded channel alliances with internationally recognized
brands such as MSN, Yahoo! and Google”


Vulnerable Application is Hosted by 3rd Party

 Routing of users from Yahoo! to Astroyogi.com with a DNS
alias
 “in.horoscopes.lifestyle.yahoo.net”“yahoo.astroyogi.com”


You Don’t Own the Code of All Your Applications

 Yahoo! is not alone
 3rd party applications are embedded as code or by
hosting by many organizations
 28% of Veracode assessed applications are identified as
created by a 3rd party


You Don’t Even Own All the Code of YOUR
Applications

 Even homegrown applications are mostly comprised of
3rd party code
 According to Veracode:
+ “Up to 70% of internally developed code originates outside of
the development team”


Third Party Code Related Breaches


Becoming Part of OWASP Top 10


Recommendations


SQL Injection
Mitigation Checklist


Step 1: Use a WAF to Detect SQL Injection

 Positives
+ Can block many attacks
+ Relatively easy

 Negatives
+ Can become a crutch
+ Potential for false positives


Step 2: Deploy Reputation Based Solution

 Positives
+ Blocks up to 40% of attack
traffic
+ Easy

 Negatives
+ Does not deal with the
underlying problem


Step 3: Stop Automated Attack Tools

 Positives
+ Detects automated tool
fingerprints to block attacks
+ Relatively easy

 Negatives
+ Potential for false positives


Step 4: WAF + Vulnerability Scanner

“Security No-Brainer #9:
Application Vulnerability Scanners
Should Communicate with
Application Firewalls”
—Neil MacDonald, Gartner

Source: http://blogs.gartner.com/neil_macdonald/2009/08/19/security-no-brainer-9-application-vulnerability-scanners-should-
communicate-with-application-firewalls/


3 rdParty Code
Mitigation Checklist


Technical Level Recommendations

 Assume third-party code – coming from partners,
vendors, or mergers and acquisitions – contains
serious vulnerabilities
 Pen test before deployment to identify these issues
 Deploy the application behind a WAF to
+ Virtually patch pen test findings
+ Mitigate new risks (unknown on the pen test time)
+ Mitigate issues the pen tester missed
+ Use cloud WAF for remotely hosted applications
 Virtually patch newly discovered CVEs
+ Requires a robust security update service


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Lessons Learned From the Yahoo! Hack

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