Thursday, May 18, 2017

Terror Evolved: Exploit Kit Matures

This post is authored by Holger Unterbrink and Emmanuel Tacheau


Executive Summary


Talos is monitoring the major Exploit Kits(EK) on an ongoing basis. While investigating the changes we recently observed in the RIG EK campaigns, we identified another well known candidate: Terror Exploit Kit.

Terror EK is one of the new players who showed up after the big Exploit Kit market consolidation last year. When Angler and friends disappeared new EKs started to try their luck. Many of them were far from Angler’s quality. One of these was Terror EK which appeared end of last year. It started with a very simple version,carpet bombing the victims with many exploits at the same time, no matter if the exploit matched the victim's browser environment or not. Unfortunately, they improved the kit step by step and we saw a fast evolution up to the latest version analysed in this report.

We identified a potentially compromised legitimate web site acting as a malware gate, redirecting visitors initially to a RIG exploit kit landing page, then switching to Terror exploit kit one day later.

This may indicate how these campaigns collaborate and share resources, or possibly one campaign pirating another. Terror seems to constantly evolving. In this campaign it has added further exploits and no longer carpet bombs the victim. Instead it evaluates data regarding the victim's environment and then picks potentially successful exploits depending on the victim's operating system, patch level, browser version and installed plugins. This makes it harder for an investigator to fully uncover which exploits they have.

It is interesting to note that the adversaries are using an URL parameter in cleartext for the vulnerability they are going to exploit, e.g. cve2013-2551 = cve20132551 in the URL.

Wednesday, May 17, 2017

Beers with Talos Podcast Now Available

The first episodes of Beers with Talos are now available on iTunes and directly on talosintelligence.com/podcasts.



When Talos decided to make a threat intelligence podcast, we wanted to make it different than your typical buttoned down, subdued security podcast. The BWT crew: Craig, Joel, Nigel, and Mitch, decided to do that by making a podcast that is a lot like the discussions that you would have after work with colleagues - if your colleagues were both ridiculously opinionated and hyper-focused on security research. Occasionally we’ll even have some special guests join us.

At its core, Beers with Talos is four people from Talos unpacking some of the biggest recent security stories from various perspectives and making (terrible) jokes the whole time. It doesn’t matter if you are a grizzled SOC vet, a researcher, an executive, or you just want to stay informed about the threat landscape, everyone can take something away with them at the end of an episode. Check out the episodes we have released and let us know what you think and what topics you might want to hear covered or guest you would like us to invite for future episodes.

You can listen and subscribe on iTunes (or directly to our RSS feed if that’s your style). We would love to hear your feedback and ideas for future episodes - tweet @TalosSecurity using #BWT or you can email us at BeersWithTalos@cisco.com.

Tuesday, May 16, 2017

Arbitrary Code Execution Vulnerabilities in MuPDF Identified and Patched

Talos is disclosing the presence of two vulnerabilities in the Artifex MuPDF renderer. MuPDF is a lightweight PDF parsing and rendering library featuring high fidelity graphics, high speed, and compact code size which makes it a fairly popular PDF library for embedding in different projects, especially mobile and web applications. Both of these vulnerabilities, if exploited, could lead to arbitrary code execution of an attacker's choice on the target device. Both of these vulnerabilities have been responsibly disclosed and Artifex has released software updates to address these vulnerabilities.

Vulnerability Details

Two memory corruption vulnerabilities exist within Artifex MuPDF render that could result in arbitrary code execution if exploited. These two vulnerabilities manifest as a result of improperly parsing and handling parts of a PDF file.

Friday, May 12, 2017

Player 3 Has Entered the Game: Say Hello to 'WannaCry'

This post was authored by Martin Lee, Warren Mercer, Paul Rascagneres, and Craig Williams.


Executive Summary


A major ransomware attack has affected many organizations across the world reportedly including Telefonica in Spain, the National Health Service in the UK, and FedEx in the US. The malware responsible for this attack is a ransomware variant known as 'WannaCry'.

The malware then has the capability to scan heavily over TCP port 445 (Server Message Block/SMB), spreading similar to a worm, compromising hosts, encrypting files stored on them then demanding a ransom payment in the form of Bitcoin. It is important to note that this is not a threat that simply scans internal ranges to identify where to spread, it is also capable of spreading based on vulnerabilities it finds in other externally facing hosts across the internet.

Additionally, Talos has observed WannaCry samples making use of DOUBLEPULSAR which is a persistent backdoor that is generally used to access and execute code on previously compromised systems. This allows for the installation and activation of additional software, such as malware. This backdoor is typically installed following successful exploitation of SMB vulnerabilities addressed as part of Microsoft Security Bulletin MS17-010. This backdoor is associated with an offensive exploitation framework that was released as part of the Shadow Brokers cache that was recently released to the public. Since its release it has been widely analyzed and studied by the security industry as well as on various underground hacking forums.

WannaCry appears to primarily utilize the ETERNALBLUE modules and the DOUBLEPULSAR backdoor. The malware uses ETERNALBLUE for the initial exploitation of the SMB vulnerability. If successful it will then implant the DOUBLEPULSAR backdoor and utilize it to install the malware. If the DOUBLEPULSAR backdoor is already installed the malware will still leverage this to install the ransomware payload. This is the cause of the worm-like activity that has been widely observed across the internet

Organizations should ensure that devices running Windows are fully patched and deployed in accordance with best practices. Additionally, organizations should have SMB ports (139, 445) blocked from all externally accessible hosts.

Please note this threat is still under active investigation, the situation may change as we learn more or as our adversary responds to our actions. Talos will continue to actively monitor and analyze this situation for new developments and respond accordingly. As a result, new coverage may be developed or existing coverage adapted and/or modified at a later date. For current information, please refer to your Firepower Management Center or Snort.org.

Threat Round-up for May 05 - May 12

Today, Talos is publishing a glimpse into the most prevalent threats we've observed between May 05 and May 12. 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.

Jaff Ransomware: Player 2 Has Entered The Game

This post was written by Nick Biasini, Edmund Brumaghin and Warren Mercer with contributions from Colin Grady

Summary


Talos is constantly monitoring the email threat landscape and tracking both new threats as well as changes to existing threats. We recently observed several large scale email campaigns that were attempting to distribute a new variant of ransomware that has been dubbed "Jaff". Interestingly we identified several characteristics that we have previously observed being used during Dridex and Locky campaigns. In a short period of time, we observed multiple campaigns featuring high volumes of malicious spam emails being distributed, each using a PDF attachment with an embedded Microsoft Word document functioning as the initial downloader for the Jaff ransomware. While Cisco customers were already automatically protected against this threat, we decided to take a deeper look at this threat and its possible implications across the threat landscape. We have outlined the infection process and additional relevant information regarding this threat in detail below.

Vulnerability Spotlight: Hangul Word Processor Remote Code Execution Vulnerability

Vulnerability discovered by Rich Johnson of Talos.

Overview


Published by Hancom inc. the Hangul Office Suite, of which Hangul Word Processor is part, is the leading word processing and office productivity suite in South Korea. This vulnerability allows attackers to craft a malicious document that when opened, allows the attacker to cause arbitrary code to be executed on the victim’s system.

Tuesday, May 9, 2017

Microsoft Patch Tuesday - May 2017

Today, Microsoft has release their monthly set of security updates designed to address vulnerabilities. This month's release addresses 56 vulnerabilities with 15 of them rated critical and 41 rated important. Impacted products include .NET, DirectX, Edge, Internet Explorer, Office, Sharepoint, and Windows.

In addition to the coverage Talos is providing for the normal monthly Microsoft security advisories, Talos is also providing coverage for CVE-2017-0290, the MsMpEng Malware Protection service vulnerability in Windows reported by Natalie Silvanovich and Tavis Ormandy of Google Project Zero. Snort rule SIDs for this specific vulnerability are 42820-42821.

Monday, May 8, 2017

Vulnerability Spotlight: WolfSSL library X.509 Certificate Text Parsing Code Execution Vulnerability

Discovered by Aleksandar Nikolic of Cisco Talos

Overview

Talos is disclosing TALOS-2017-0293 / CVE 2017-2800, a code execution vulnerability in WolfSSL. WolfSSL is a lightweight SSL/TLS library targeted specifically for embedded and RTOS (Real-Time Operating System) environments, due largely to its small size and performance. WolfSSL is used in a wide range of products including ICS and IoT devices.

This particular vulnerability is related to the use of x.509 certificates and the code that deals with string fields in DER certificates. Specifically the code responsible for parsing 'commonName', 'countryName', 'localityName', 'stateName', 'orgName', and 'orgUnit'. A specially crafted x.509 certificate can cause a single out-of-bounds overwrite that could result in certificate validation issues, denial of service, or remote code execution. To trigger this vulnerability, the adversary needs to supply a malicious x.509 certificate to either the server or client application that is making use of this library. The full details surrounding the vulnerability are available here.

Friday, May 5, 2017

Vulnerability Spotlight: Power Software PowerISO ISO Code Execution Vulnerabilities

These vulnerabilities were discovered by Piotr Bania of Cisco Talos.

Today, Talos is releasing details of a new vulnerability discovered within the Power Software PowerISO disk imaging software. TALOS-2017-0318 and TALOS-2017-0324 may allow an attacker to execute arbitrary code remotely on the vulnerable system when a specially crafted ISO image is opened and parsed by the PowerISO software.

Overview


The vulnerabilities are present in the Power Software PowerISO disk imaging utility, used by Windows users to create, edit, mount and convert various popular disk image file formats. The software is commonly used by home users to mount ISO disk images since this capability is not included by default in Windows versions prior to version 8.

ISO (9660) disk image format is a file system within a single file. Essentially, it is a binary copy of the file system used by the standard software CD-ROM installation disks. Today, most of the installation disks for popular software and operating systems are distributed using the ISO file format.