Adjusting the Anchor

Overview AnchorDNS is a backdoor used by the TrickBot actors to target selected high value victims. It has been seen delivered by both TrickBot and Bazar1 malware campaigns2. AnchorDNS is particularly difficult to track given that it is deployed only post-infection and that too only after a period of reconnaissance, once the malware operators have established that the target is of special interest. Following analysis of AnchorDNS samples published in recent reporting23, we have observed that the C2 communications protocol of AnchorDNS has changed.

TrickBot and Zeus

Overview TrickBot is an established and widespread multi-purpose trojan. Active since 2016 and modular in nature, it can accomplish a variety of goals ranging from credential theft to lateral movement. Many of the malware’s capabilities come as self-contained modules, which the malware is instructed to download from the C2. Initially, TrickBot’s main focus was bank fraud, but this later shifted toward corporate targetted ransomware attacks, eventually resulting in the discontinuation of their fraud operation.

TrickBot masrv Module

Overview Active since 2016, TrickBot is one of the most prevalent modular banking trojans. The botnet’s modules carry out objectives such as credential harvesting, propagating via the network, web injection and others. Being an actively developed botnet, we often come across updated modules and in some cases new tools that are added as part of its arsenal. Recently we have discovered a relatively new module that goes by the name masrv.

Faster Poly1305 key multicollisions

It is well known by now that encryption without authentication is insufficient, and many chosen-ciphertext attacks on improperly authenticated ciphertexts are now commonplace. Authenticated encryption—constructions that both encrypt and authenticate plaintexts in one sitting—are widespread at this point, with the two most common instances being AES-GCM and ChaChaPoly1305. One property that the usual definitions of authenticated encryption do not capture is key commitment: a ciphertext is tied to a particular key, and it should not be possible to create ciphertexts that successfully decrypt under more than one key.

Automated string de-gobfuscation

Last week the Network Security Research Lab at 360 released a blog post on an obfuscated backdoor written in Go named Blackrota. They claim that the Blackrota backdoor is available for both x86/x86-64 architectures which is no surprise given how capable Golang’s cross compilation is. For the last 4 years we have been using Golang for our internal services, and I can definitely see the allure that Golang has for malware authors:

Another look at two Linux KASLR patches

A fast pseudorandom generator for KASLR A recent patchset proposed for the Linux KASLR randomizes not only the kernel base address, but also reorders every function at boot time. As such, it no longer suffices to leak an arbitrary kernel function pointer, or so the logic goes. Along with this patchset came a custom random number generator intended to be as fast as possible, so as to keep the boot time overhead at a minimum:

RDP to RCE: When Fragmentation Goes Wrong

Remote Desktop Gateway (RDG), previously known as Terminal Services Gateway, is a Windows Server component that provides routing for Remote Desktop (RDP). Rather then users connecting directly to an RDP Server, users instead connect and authenticate to the gateway. Upon successful authentication, the gateway will forward RDP traffic to an address specified by the user, essentially acting as a proxy. The idea is that only the gateway needs to be exposed to the Internet, leaving all RDP Servers safely behind the firewall.

BlueKeep (CVE 2019-0708) exploitation spotted in the wild

Overview It has been almost six months since an eye opening vulnerability in Microsoft Windows RDP CVE 2019-0708, dubbed BlueKeep, was patched. Today, Security Researcher Kevin Beaumont posted a Twitter thread reporting BSODs (Blue Screen of Death) across his network of BlueKeep Honeypots. huh, the EternalPot RDP honeypots have all started BSOD'ing recently. They only expose port 3389. pic.twitter.com/VdiKoqAwkr — Kevin Beaumont (@GossiTheDog) November 2, 2019 Kevin kindly shared the crash dump with us and following this lead, we discovered the sample was being used in a mass exploitation attempt.

Emotet scales use of stolen email content for context-aware phishing

Overview Emotet’s automated targeting phishing campaigns have arrived and they are aggressive. As originally discovered and predicted in our previous post about Emotet’s mass email harvesting, computers infected with Emotet and the email harvesting module could be used to create believable emails which even savvy email users may be tricked into clicking. Since then, Kryptos' Threat Intelligence Team has observed Emotet’s behavior evolve, with the aid of their stolen email troves.

North Korean APT(?) and recent Ryuk Ransomware attacks

Our Threat Intelligence team has been tracking the Emotet botnet throughout 2018. In our previous post we reported a large scale Emotet campaign focused on e-mail content exfiltration. Today, we review the evidence gathered from our Telltale Threat Intelligence Service, which suggests the involvement of Emotet as the delivery mechanism for the latest wave of Ryuk ransomware attacks being dubbed as North Korean state-sponsored cyber-attacks. The evidence from the dataset completes the missing narrative needed to show a likely and complete attack chain of compromise via organized crimeware activity.

Emotet Awakens With New Campaign of Mass Email Exfiltration

The Emotet malware family just raised the stakes by adding email exfiltration to its arsenal, thereby escalating its capabilities to cyber espionage. While it has recently made headlines for delivering ransomware payloads to United States infrastructure such as Water Utilities, Emotet has laid mostly dormant for the past month. In the past days, however, the mummy has returned just in time for Halloween as we observed a new module capable of exfiltrating email content back to the botnet’s operators.

Inside Look at Emotet's Global Victims and Malspam Qakbot Payloads

The Emotet botnet reputation precedes it; historically aggressive and malicious, today it has evolved and incorporated a number of advancements to create a more resilient botnet delivery system, nearly immune from takedown. Recently, US CERT reported that Emotet incidents (and its subsequent payload droppers) are affecting state, local, tribal, and territorial (SLTT) governments at up to 1 million dollars per incident. We have captured a global view of many of the active infections within the latest Emotet botnet.

A Brief Look At North Korean Cryptography

With much attention lately over North Korea and its evolving cybersecurity capabilities, we thought to cover a somewhat related topic. A couple of years back, the North Korean Red Star OS was described at the Chaos Computer Club conference. Among other things, they described the watermarking mechanism used by the OS to keep track of media files. Along with the OS, three kernel modules were identified that appeared to contain homemade encryption algorithms specific to Red Star OS.

Introducing Telltale and Addressing the Lingering Wannacry Threat

In light of the recent news circulating about sporadic WannaCry outbreaks, namely defense contractor Boeing and earlier last month Connecticut state agencies, as well as Honda, we think it important to provide further guidance on assessing ongoing and hidden dangers related to WannaCry outbreaks. To immediately begin reducing risk and augmenting your existing security defenses, we are providing at no cost Telltale, a free version of Vantage Breach Intelligence Feed. Telltale is a simplified version of our breach monitoring and can help your organization assess past or ongoing malware infections, including but not limited to WannaCry.

WannaCry: End of Year Retrospective

Last November marked the six-month anniversary of WannaCry, arguably the most impactful global cyberattack in history. The persisting WannaCry attack is a re-purposed ransomware strain amplified by (allegedly) leaked exploit code from the NSA. For previous details about the inner workings of WannaCry see our previous post. Today, the United States declared North Korea responsible for the WannaCry attacks. This post will present analytical findings and perspective into just how wide these attacks have scaled, and how very little footprint is required to sustain a global security crisis.

Petya, Dead but Still Dancing

There are a few interesting things to say about the current ransomware Petya. One thing is clear, there is no “kill-switch”. After some preliminary tracking of the domains which presumably deliver the payload for its RTF (Windows document exploit) delivery system and cross referencing it to passive intelligence about the domain name, we noticed the frequency of 2 million hits within an hour. The domains we tracked are not currently serving the payload and are down.

WannaCry: Two Weeks and 16 Million Averted Ransoms Later

WannaCrypt, aka WannaCry, has been the Infosec story of the past couple of weeks. What was originally a humble ransomware became a newly retrofitted NSA-powered worm which spread recklessly, wreaking global havoc. Fortunately, the proliferation of WannaCry came to a standstill when one of our security researchers, MalwareTech, working to collect intelligence for the Vantage Breach Intelligence Feed, registered a domain associated to the malware, ultimately triggering its “kill switch”.