Researcher Finds Flaws In Key Oracle Security Feature

David Litchfield calls Oracle's new data redaction feature for its database software a "clever" concept for protecting sensitive information. But it turns out the new option in Oracle's 12c database -- which allows organizations to redact or hide from unauthorized eyes sensitive data such as social security or credit-card numbers in a database lookup -- can be cheated altogether and also allow an attacker to exploit weaknesses in the code via a Web-based SQL injection attack.

Oracle's data redaction feature lets a database administrator selectively or fully redact or mask sensitive data in SQL query results so users only see the data they are authorized to see. Oracle also provides an update to its 11g Release 2 database that adds the feature.

Troy Kitch, principal director of security software at Oracle, wrote in a blog post last year announcing the new feature:

Data Redaction provides selective, on-the-fly redaction of sensitive data in SQL query results prior to application display so that unauthorized users cannot view the sensitive data. It enables consistent redaction of database columns across application modules accessing the same database information …

Unlike historical approaches that relied on application coding and new software components, Data Redaction policies are enforced directly in the database kernel.

But Litchfield, who is well-known for keeping Oracle on its toes security-wise with his research, tested the feature and found that it could be bypassed. "It seems there are a whole range of things wrong with it," Litchfield says. "It suggests they didn't do an assessment on it before they shipped it. They didn't [apparently perform] a penetration test on it."

"It's a brilliant idea in practice, to redact data from a curious person" querying the database, he says. The feature won't stop a database administrator from seeing the redacted data, he says, so if an attacker is able to escalate his privileges, he can access the hidden information.

But there also are ways an attacker could access the redacted data basically by bypassing the feature itself, Litchfield found. An outside attacker also could reach the hidden data via a Web-based SQL injection flaw using the same bypass techniques, he says. 

Litchfield plans to demonstrate those hacks at Black Hat USA next month. He says he reported the flaws to Oracle in November, and Oracle is currently working on fixes.

[Famed Oracle security researcher David Litchfield will discuss vulnerabilities he found in a key database security feature. Read Dark Reading Radio: Oracle Database Security Hacked.]

But the good news with this security feature is that there's no major risk today by using it in the database, Litchfield says. He says he expects data redaction to be a popular feature for protecting sensitive data.

"To be fair, it's a good step in the right direction," he says. "Even if a patch isn't available from Oracle, it's going to protect you in 80% of the cases. No one really knows how to bypass it at this point."

Litchfield is the guest on Dark Reading Radio today at 1:00 p.m. ET, where he will discuss his findings and take questions from the audience via a live online chat. To tune in for the show, register here.