Today, Talos is publishing a glimpse into the most prevalent threats we’ve observed between June 02 and June 09. As with previous round-ups, this post isn’t meant to be an in-depth analysis. Instead, this post will summarize the threats we’ve observed by highlighting key behavior characteristics, indicators of compromise, and how our customers are automatically protected from these threats.
As a reminder, the information provided for the following threats in this post is non-exhaustive and current as of date of publication. Detection and coverage for the following threats is subject to updates pending additional threat or vulnerability analysis. For the most current information, please refer to your Firepower Management Center, Snort.org, or ClamAV.net.
Technological progress is resulting in computing systems that are smaller, cheaper and consuming less power. These micro-computing systems are able to be integrated into everyday objects; when coupled with ubiquitous wireless connectivity these devices form the “Internet of Things”. The IoT has the potential to improve our lives, but only if we correctly manage the security risks which are inherent to these devices.
Beers with Talos Episode 5 “It Has Been 0-days Since This Term was Abused” is now available. Beers with Talos offers a topical, fast-paced, and slightly irreverent take on cybersecurity issues. If you are an executive, a grizzled SOC vet, or a n00b, you will take something away from each episode. We won’t promise it’s anything good… but it’s something.
In this episode: Craig, Joel, Matt, Nigel and Mitch cover the potential of Samba echoing WannaCry and blocking SMB ports (but you already did that, RIGHT?). There is also some history lessons to give proper usage guidance on words like 0-days, backdoors, and other terms that the industry loves to hype and abuse for extra clicks.
Today, Talos is publishing a glimpse into the most prevalent threats we’ve observed between May 19 and May 26. As with previous round-ups, this post isn’t meant to be an in-depth analysis. Instead, this post will summarize the threats we’ve observed by highlighting key behavior characteristics, indicators of compromise, and how our customers are automatically protected from these threats.
As a reminder, the information provided for the following threats in this post is non-exhaustive and current as of date of publication. Detection and coverage for the following threats is subject to updates pending additional threat or vulnerability analysis. For the most current information, please refer to your FireSIGHT Management Center, Snort.org, or ClamAV.net.
Today, a new vulnerability affecting the widely used Samba software was released. Samba is the SMB/CIFS protocol commonly used in *NIX operating systems. CVE-2017-7494 has the potential to impact many systems around the world. This vulnerability could allow a user to upload a shared library to a writeable share on a vulnerable Samba server and result in the server executing the uploaded file. This would allow an attacker to upload an exploit payload to a writeable Samba share, resulting in code execution on any server running an affected version of the Samba package. This currently affects all versions of Samba 3.5.0 (released March of 2010) and later. To emphasize the severity and low complexity: a metasploit one-liner can be used to trigger this vulnerability.
A patch has already been released to address the issue. Additionally, there is a mitigation available within the configuration of Samba itself. Adding the argument “nt pipe support = no” to the global section of the smb.conf file and restarting the service will also mitigate the threat. This threat is only beginning to be recognized by potential attackers with POC code having already been released on the Internet. It is only a matter of time before adversaries begin to use it more widely to compromise additional systems, both externally and internally.
This post was authored by Martin Zeiser with contributions by Joel Esler
At Talos we are constantly on the lookout for threats to our customers networks, and part of the protection process is creating Snort rules for the latest vulnerabilities in order to detect any attacks.
To improve your understanding of the rule development process, consider a theoretical remotely exploitable vulnerability in server software Server2010. A proof-of-concept exploit is developed, the server software set up on a virtual machine, traffic is captured on the network between attacker and victim, rule development can start, right?
But what if months or years later, the rule needs to be re-inspected, because circumstances have changed? This requires another vulnerable version of Server2010 to be found, reinstalled and reconfigured to the vulnerable parameters, to run tests again and again, so that network traffic can be inspected. Then when the server is installed, the particular exploit used does not work anymore, because the language it was written in has since changed and the code needs to be fixed accordingly. All this requires plenty of time, which is why it doesn’t happen that way. Instead, a vulnerability is identified, an exploit is written, the exploit is ran, and the attack captured using Wireshark. From then on, the traffic in said pcap file can be used to develop a correct rule. The traffic recorded in a pcap file can easily be put back on the wire using a tcp replay utility, or read directly by Snort. This is why rule developers generally work with pcaps of attacks, instead of exploits.
Regarding file-based vulnerabilities, the original process used to involve starting a local webserver and using a browser to download the exploit file, while recording the transfer using Wireshark. File2pcap revolutionized this requirement by simulating the traffic and creating the proper pcap without any hassles.