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Oracle database flaw deemed serious, could expose data

Antone Gonsalves | Sept. 24, 2012
With brute-force attack, intruder can gain access

Some Oracle databases have what experts say is a serious flaw in the login system that a hacker can use to retrieve and change stored data.

The flaw, in Oracle Database 11g Releases 1 and 2Ã'Â leaves the token that is provided by the server before authentication is completed open to a brute-force attack, said Esteban Martinez Fayo, the Application Security researcher that discovered the flaw. If successful, an attacker can gain access to the database.

"An authentication bypass is quite serious," Kevin Mitnick, a well-known white-hat hacker and founder of Mitnick Security Consulting, said in an email. "Basically, an attacker can get to the data stored in the database, and even change it."

The vulnerability stems from the way the authentication protocol protects session keys. When a client connects to the database server, a session key is sent with a salt. Because this happens before the authentication process is finished, a hacker working remotely can link the key to a specific password hash.

"Once the attacker has a session key and a salt, the attacker can perform a brute-force attack on the session key by trying millions of passwords per second until the correct one is found," Fayo toldÃ'Â Kaspersky Lab'sÃ'Â Threatpost blog.Ã'Â

Because the hack occurs before authentication is done, no login failure is recorded in the server, so a person can gain access without triggering an abnormal event.

[See also: Database security - At rest, but not at risk]

Oracle, which did not respond to a request for comment, patched the flaw in the latest upgrade of the authentication protocol, version 12. However, the company is not planning a patch for the flawed version, 11.1, Fayo said. Even with the upgrade, database administrators have to configure the server to only allow the new version of the protocol.

Because the fix requires an upgrade, the vulnerability will hound some Oracle customers for years, said Justin Clarke, a security researcher at Cylance.

"There are many large companies and critical infrastructure agencies which cannot afford the time or risk to upgrade all their Oracle clients and servers," Clarke said. "I can say with near certainty that we will see this vulnerability as long as Oracle 11g remains in use."

Previous flaws in Oracle's authentication protocol have been a well-kept secret in the security industry, Clarke said. "It's great to see that issues like this are being discussed publicly, and I hope that this helps serve as a wake-up call for Oracle and its users to dig deeper and assess the actual strength of systems."

Brent Huston, chief executive of security testing company MicroSolved, said even if a company prevents Internet access to a vulnerable database, the data is still at risk of an attack from the inside.


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