Oracle flaw that allows massive DDoS attacks

Posted by & filed under Ειδοποιήσεις.

Oracle has just released a security update to prevent 2.3 million servers running the RPCBIND service from being used in amplified DDoS attacks.

The flaw was discovered by the Brazilian researcher Mauricio Corrêa, founder of Brazilian security company XLabs. The exploitation of this vulnerability could cause major problems on the Internet.

“A proof of concept (POC) made in only one XLabs server generated a traffic of 69 gigabits per second,” Mauricio said.

At the time of the discovery, the expert queried Shodan and found that there were nearly 2.6 million servers running RPCBIND on the Internet. The multiplication of this exploit in a 2.6 million server farm leads to a frightening conclusion.

RPCBIND is software that provides client programs with the information they need about server programs available on a network. It runs on port 111 and responds with universal addresses of the server programs so that client programs can request data through RPCs (remote procedure calls).

These addresses are formed by the server IP pool plus port. Since its launch, RPCBIND has been receiving updates that cover several failures, including security. This, however, is the most serious finding so far.

The discovery of the crash began on June 11 this year. On that day, one of the web application firewalls (WAFs) installed in the XLabs SOC (security operations center) detected an abnormal pattern of network traffic that caught the eye of Mauricio.

The data showed that a DDoS attack was in progress, coming from port 111 of several servers, all from other countries.

“We then decided to open a server with port 111 exposed on the Internet, with the same characteristics as those who were attacking us and we were monitoring that server for weeks. We found that he was receiving requests to generate attacks, ” he explained. 

After further analysis of the subject, it was possible to reproduce the attack in the laboratory.

“By analyzing the servers exposed at Shodan, the extent of the problem was confirmed,” continues Mauricio.

The problem discovered by Mauricio is worse than Memcrashed, detected in February of this year. In this type of distributed denial of service (DDoS) attack, the malicious traffic generated with the technique is greater than the once associated with the use of memcached, a service that does not require authentication but has been exposed on the internet by inexperienced system administrators. The service runs on UDP port 11211 and its exploitation by cybercriminals has already generated 260GB traffic according to Cloudflare company measurements.

After developing the POC, Maurício reported the problem to Oracle’s security team, since RPCBIND is a solution originating from Sun, which was acquired by the company in 2010. He sent the information to Oracle so that the experts of the company could confirm and evaluate the problem.


The information contained in this website is for general information purposes only. The information is gathered from Security Affairs while we endeavour to keep the information up to date and correct, we make no representations or warranties of any kind, express or implied, about the completeness, accuracy, reliability, suitability or availability with respect to the website or the information, products, services, or related graphics contained on the website for any purpose. Any reliance you place on such information is therefore strictly at your own risk.
Through this website, you are able to link to other websites which are not under the control of CSIRT-CY. We have no control over the nature, content and availability of those sites. The inclusion of any links does not necessarily imply a recommendation or endorse the views expressed within them.
Every effort is made to keep the website up and running smoothly. However, CSIRT-CY takes no responsibility for, and will not be liable for, the website being temporarily unavailable due to technical issues beyond our control.