The security world has been shocked to its foundations following ominous warnings that millions of Drupal websites that didn't apply a critical patch within hours of its release earlier this month should be regarded as hopelessly compromised.
The maintainers of the Drupal content management system warned users that “automated attacks” targeting Drupal version 7 began just hours after they disclosed a highly critical SQL injection vulnerability on 15 October.
“Proceed under the assumption that every Drupal 7 website was compromised unless updated or patched before Oct 15th, 11pm UTC," Drupal said in an "Highly Critical - Public Service announcement" on Wednesday.
The vulnerability in Drupal 7.x could be exploited to gain elevated privileges or execute PHP code through SQL injection attacks. Earlier versions of Drupal were NOT affected by the flaw, which ironically stems from code designed to guard against SQLi attacks.
The CVE-2014-3704 flaw creates a means for hackers to steal information, or much worse, plant malicious code or backdoors on servers running the vulnerable enterprise app. Upgrading to Drupal 7.32 fixes the vulnerability, without removing any backdoors installed by hackers if they managed to compromise a site before it was patched.
In some cases it seems that hackers actually patched vulnerable systems themselves – not as an act of charity but to prevent rival hacking groups getting in.
Finding out if there's a backdoor on a website is a difficult and uncertain business. So rather than simply patching, more drastic action is needed. Drupal’s advice is if there's any doubt then sites need to be rebuilt using backups that pre-date 15 October – or they need to be rebuilt from scratch.
"In a nutshell, if your site wasn’t protected within a few hours of Drupal’s announcement on 15 October, you need to restore it from an old backup or rebuild it from the ground up," said veteran security expert Graham Cluley, in a blog post. "Drupal’s advice will be a hard pill for some sites to follow, but should mean that you can feel confident that your site is not affected.
Gavin Millard, EMEA Technical Director at Tenable Network Security, developers of the Nessus vulnerability scanner, questioned Drupal's handling of the disclosure.
"The issues highlighted by the Drupal team could have been reduced if responsible disclosure followed," Millard said. "Announcing a fundamental flaw in the code to everyone without giving much runway to the users of Drupal to proactively patch, gives ample time for attackers to weaponise the flaw and exfiltrate data or manipulate the systems for later exploitation.”
Ilia Kolochenko, chief exec of web security testing firm High-Tech Bridge, said the circumstances of the flaw made Drupal sites easy picking for even relatively unskilled miscreants.
“As soon as a vulnerability in popular CMS platforms like Drupal is discovered, millions of crawlers operated by hackers (similar to Google bots) start searching for vulnerable websites," Kolochenko explained. "Once a victim is identified, their website gets hacked, patched (to prevent ‘competition’ taking over the same site) and backdoored.”
“Within several days, access to the compromised website will be sold on the black market, more than likely to several different customers at the same time who each may well resell it several more times. Like this, your personal blog may be easily involved in a dozen different criminal offences such as hosting illicit content, sending spam and infecting visitors,” Kolochenko concluded.
Tenable's Millard agreed that the bug was easily exploitable.
“The so-called 'Drupageddon' vulnerability could have easily led to exploitation of any systems running the vulnerable code," Millard said. "With such an easy to exploit flaw, the chance of exfiltration of data or further exploitation are high."
Reviewing log files for signs of attacks would be prudent in the circumstances, Millard concluded.
"For those who have good security controls, reviewing of logs and traffic directed at the sites following the vulnerability being announced and the patch applied is common sense and highly advisable, with appropriate action taken if indicators of compromise are found.”
“For those who don’t have such a good level of security or visibility into the logs, the advice from the Drupal team should be heeded. If you don’t know if you were exploited you should assume that you have been." ®