Wednesday, June 18, 2008

The Zeus Crimeware Kit Vulnerable to Remotely Exploitable Flaw

Just like you have sophisticated cyber criminals trying to scam wannabe cyber criminals by providing them with backdoored web malware exploitation kits and phishing pages, you have cyber criminals looking for ways to obtain access to the most popular exploitation kits and bankers malware C&Cs by finding vulnerabilities within them.

Apparently, Zeus, the crimeware kit which I discussed in a previous post, is susceptible to a remotely exploitable vulnerability according to a proof of concept code I obtained recently . The vulnerability allows the injection of logins and passwords within any misconfigured web interface, due to the way in which Zeus is processing php scripts (web shells and backdoors) from the directory in which it stores the stolen data. Ironically, "Zeus users are advised to take care of their directory permissions, and forbid the execution of scripts from the folder holding all the encrypted stolen information".

The implications of this flaw are huge, since, what used to be the practice of hijacking someone's misconfigured botnet a couple of years ago, is today's hijacking of the malware campaigns's command and control interface, which on the majority of occasions is left accessible to everyone - including independent researchers and the security community.

Picture the following situation - right before the Russian Business Network "disappeared", it threatened to sue Spamhaus for blacklisting most of its old infrastructure, what would happen if the security community starts unethically pen-testing the RBN's infrastructure, and remotely exploit misconfigured Zeus C&Cs in order to estimate the number of infected hosts and the type of stolen data in order to communite its findings to the appropriate parties on all fronts? If the RBN starts suing for getting unethically pen-tested, it would automatically claim ownership of, well, the Russian Business Network's infrastructure which you must be pretty familiar with by now.

Moreover, can we even dare to speculate on the existence of monoculture in crimeware software? You bet, and finding vulnerabilities within popular crimeware kits and web malware exploitation kits is only starting to emerge, a situation where the market share of a certain kit would attract the most vulnerability research.