The developers of the popular malware analysis framework Cuckoo Sandbox were forced to take quick action on Tuesday after being notified of the existence of a serious vulnerability that can potentially be exploited to take control of affected systems.
The flaw was uncovered by researchers at security firm G Data Software who reported their findings to Cuckoo Sandbox developers on October 7. The issue was addressed just hours later with the release of Cuckoo Sandbox 1.1.1.
The vulnerability, which affects all versions of the malware analysis framework starting with version 0.6, allows an attacker to upload arbitrary files from the virtual machine to the host system. This sandbox evasion could lead to arbitrary code or command execution.
“Due to an insufficient sanitizing of the ‘buf’ variable, an attacker could craft an executable that, when analyzed by the sandbox, would instruct the Cuckoo daemon to create or overwrite any arbitrary file on the host system. Under some circumstances, this could lead to command or code execution on the host system, from within the virtual machine. The issue relies on some behavior from Python’s os.path.join() function that we did not expect,” Cuckoo Sandbox developers wrote in a blog post accompanying the software update.
G Data has pointed out that the open source software is used by law enforcement, security firms, and independent researchers. However, since it’s free, it’s mostly popular among independent researchers and smaller organizations.
“Generally speaking, this attack allows it for malware authors to break into the systems of those that are trying to fight them,” G Data explained in a blog post. “This can be achieved by writing tailored malware that actively tries to exploit Cuckoo sandboxes. Prerequisite is that the attackers can enforce to be executed by a Cuckoo sandbox instance, for example by uploading the malicious files to a public web interfaces to an analysis framework.”
The vulnerability has been addressed with a simple hotfix, but Cuckoo Sandbox developers say they will reconsider the design of the vulnerable mechanism in the current development branch.