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Exploit code for wormable flaw on unpatched Windows devices published online

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A researcher has published exploit code for a Microsoft Windows vulnerability that, when left unpatched, has the potential to spread from computer to computer with no user interaction.

So-called wormable security flaws are among the most severe, because the exploit of one vulnerable computer can start a chain reaction that rapidly spreads to hundreds of thousands, millions, or tens of millions of other vulnerable machines. The WannaCry and NotPetya exploits of 2017, which caused worldwide losses in the billions and tens of billions of dollars respectively, owe their success to CVE-2017-0144, the tracking number for an earlier wormable Windows vulnerability.

Also key to the destruction was reliable code developed by and later stolen from the National Security Agency and finally published online. Microsoft patched the flaw in March 2017, two months before the first exploit took hold.

Puppies will die

Proof-of-concept exploit code for the new wormable Windows vulnerability was published on Monday by a Github user with the handle Chompie1337. The exploit isnt reliable and frequently results in crashes that present a BSOD, shorthand for the “blue screen of death” Windows displays during system failures. Regardless, the code still serves as a blueprint that, with more work, could be used to remotely compromise vulnerable machines and then spread.

“This has not been tested outside of my lab environment,” the Github user wrote. “It was written quickly and needs some work to be more reliable. Sometimes you BSOD. Using this for any purpose other than self education is an extremely bad idea. Your computer will burst in flames. Puppies will die.”

SMBGhost, the name given to the new Microsoft vulnerability, is likely not as easy to exploit by remote attackers, but its potential for wormable exploits and the slow rate of patching even critical security flaws have still stoked concerns among some security professionals. Microsoft has said that the chances of malicious exploits are “more likely.”

Like the flaw exploited by WannaCry and NotPetya, it resides in the Windows implementation of the Server Message Block, a service used by operating systems to share files, printers, and other resources on local networks and over the Internet. Like the older flaw, the newer one can be remotely exploited simply by sending maliciously crafted packets to a SMB port connected to the Internet.

Tracked as CVE-2020-0796, the flaw resides in Windows 10 versions 1903 and 1909 and in Windows Server versions 1903 and 1909 if they havent been patched. All are relatively new OS releases, and Microsoft has invested huge amounts of resources hardening them against precisely these types of attacks. Up until now, researchers have only been able to exploit the bug locally, meaning once they have already gained limited access in a network. By contrast, the ability to use exploits to gain RCE, short for remote code execution, have proved much more elusive.

“This is probably because remote kernel exploitation is very different from local exploitation in that an attacker can't utilize useful OS functions such as creating userland processes, referring to PEB [Process Environment Block], and issuing system calls,” researchers from Ricerca Security wrote in a detailed post published in April. “Accompanied with mitigations introduced in Windows 10, this limitation makes the achievement of RCE much more challenging.”

The result of the newly released exploit is that it increases the chances of attackers developing worms that work remotely.

Laggard, patch thyself

Reports of the vulnerability were Read More – Source

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