Exploit Kits Out, Loaders and Macros Back in

During 2016, we witnessed the collapse of three major exploit kits that were previously used for massive malware delivery: Nuclear (first), Angler and then Neutrino (later). Along with other more private EKs (such as Magnitude), they caused major damage in previous years and served as infection vectors for many malicious malware-distributing campaigns. Continue reading “Exploit Kits Out, Loaders and Macros Back in”

The Shade (Troldesh) Ransomware: One More Soldier in the Army of Encryption Miscreants

Written by Mickael S. and Tanya K.

Last week, SenseCy analysts happened upon a new sample of Shade ransomware, also known as Troldesh, which uses a no_more_ransom extension for encrypted files. This ransomware is far from famous, lacking the glorious Continue reading “The Shade (Troldesh) Ransomware: One More Soldier in the Army of Encryption Miscreants”

Insider Threats – Sometimes it is your Colleagues, and not Remote Attackers

Insiders pose the most substantial threat to organizations everywhere, a recent across-the-board study conducted by IBM demonstrates. Although in the majority of the cases, the insider is an employee of the company, he could also be a third party, such as an external contractor, a consultant or a business partner. An insider generally has all the Continue reading “Insider Threats – Sometimes it is your Colleagues, and not Remote Attackers”

Jihadi Cybercrime (Increasing Interest in Spam and Phishing Methods on Closed Islamic State Platforms)

While monitoring closed platforms that propagate an Islamic State agenda, we detected an initial interest in hacking lessons, focusing on spam and phishing methods. Many discussions in the technical sections of closed platforms affiliated with the Islamic State deal with the implementation of Continue reading “Jihadi Cybercrime (Increasing Interest in Spam and Phishing Methods on Closed Islamic State Platforms)”

Cerber Ransomware JavaScript Loader Goes Undetected

We have been closely monitoring Cerber ransomware since it first emerged on a Russian password-protected forum, offered as-a-service for members only.

At present, Cerber ransomware constitutes a sophisticated malware threat to organizations. (it was responsible for more than 25% of the total number of ransomware infections recorded worldwide in June 2016, according to Microsoft). Files encrypted by Cerber are currently non-decryptable.

On August 23, 2016, a member of the same closed forum where Cerber ransomware is traded posted a detailed analysis of the loader that the malware uses to install itself. According to his post, he did this after hearing that the loader is very useful and capable of installing any malware without detection. His conclusion was that the loader does not employ any extraordinary methods to install the ransomware, but its tremendous advantage of being fully undetectable by AV programs is due to the usage of several rare code functions that are difficult to emulate.

First, he posted the full obfuscated code of the loader, explaining parts of it:

  • Replacement of the Eval function, i.e. it receives a parameter that contains JavaScript code and executes it. Usually, AV programs emulate this function. Replacing the Eval function blocks this emulation.
  • Another part of the code creates a Desktop shortcut, probably also as an anti-emulator measure (the post writer comments that in his opinion AV would quickly detect it).
  • The next part of the code is obfuscated – a HEX code which is divided and deobfuscated using XOR.After deobfuscation, we can see that the code contains anti-emulation.
  • Then a random string is created and a path from %TEMP% environment obtained for it.
  • The next stage involves downloading the malicious file from an URL address and saving it in the system.
  • A parameter is added to the header to block AV bots and researchers: setRequestHeader(‘cerber’,’true’)
  • If the malicious payload was downloaded properly, it is executed.
  • Finally, the Eval alternative is launched.

Summarizing the analysis, the post author concludes that the advantages of the loader are a good implementation of the payload download and execution and errors control. The disadvantages he mentions are weak implementation of obfuscation and anti-emulation, and low level of usability functionality. He also attached an AV scanner report from August 23, showing a detection rate of 15/40.

Several days later, on August 27, 2016, the same forum member posted that he had analyzed the latest version of the loader and was surprised by the fact it is totally undetectable by AV programs. Moreover, this version is capable of installing payloads from several alternative URL addresses and it uses improved debugging. This version does not use anti-emulation at all, but employs a unique method that totally blocks the AV syntax emulation. 

Below is a description of the main techniques used by the loader to remain undetected:

  • Replacement of the Eval function (even though it is a simple technique, it is used extensively by JS packers and therefore cannot be detected by AV as malicious).
  • The part of the code that avoids emulation is an array that contains random data, with the first element being the important one. The functions Math.floor and Math.random always output only the first element in the array and AV cannot properly emulate them. Full undetectability is achieved by using these two functions.

The emulator will always output one single value and will never reach the part of the array when the right value is located. As a result, the emulator cannot perform the calculations, a critical error occurs and the AV programs are unable to identify the loader as a malicious file.

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The message that analyzes what code feature allows the malware to avoid AV detection

The post author attached an AV scanner report showing a 0/35 detection rate (as of August 27, 2016).

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The scan showing that the loader is not detected by AV engines

The Healthcare Sector is Targeted by Cybercriminals More than Ever

The healthcare sector has recently become a desirable target for cyber crooks. According to Symantec ISTR report statistics, healthcare was the most breached sub-sector in 2015, comprising almost 40% of all the attacks. Hospital security systems are generally less secure than those of financial organizations, as monetary theft has always been perceived as the greatest threat for organizations, and dangers to other sectors were usually underestimated. Moreover, awareness of cyber-attacks against hospitals and medical centers is much lower than it is to financial cybercrime, and as a result, the employees are less well-trained on how to avoid falling victim to a cyber-attack.

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Top 10 Sub-Sectors Breached by Number of Incidents According to Symantec ISTR report

Only lately, this concept has started to be challenged, revealing the potential damage that can be caused by the theft and leakage of patient data. However, the ‘bad guys’ remain one step ahead and during the last few months, we have witnessed a spate of attacks targeting the healthcare industry: ransomware attacks encrypting essential data and demanding payment of a ransom, numerous data leakages revealing confidential patient data, unauthorized access to medical networks and even the hacking of medical devices, such as pumps and X-ray equipment.

Moreover, the healthcare sector is being targeted by hackers not only directly, but also via third-party companies in the supply chain, such as equipment and drug suppliers. These companies usually store some confidential data that originates in the hospitals’ databases and may even have access to the hospital IT systems, but they are far less secure than the hospitals themselves. Thus, they serve as a preferable infiltration point for malicious actors pursuing the theft of medical data and attempting to infiltrate the hospitals’ networks.

The consequences of attacks on the healthcare industry may be extensive, including the impairment of the medical center functioning, which may result in danger to human lives in the worst case scenario. In other cases, personal data will be stolen and sold on underground markets. Cybercriminals will take advantages of these personal details for identity theft or for future cyber-attacks combining social engineering based on the stolen details.

While monitoring closed Deep-Web and Darknet sources, SenseCy analysts recently noticed a growing interest toward the healthcare sector among cyber criminals. Databases of medical institutions are traded on illicit marketplaces and closed forums, along with access to their servers. In the last few months alone, we came across several occurrences indicating extensive trade of medical records and access to servers where this data is stored.

The first case, in May 2016, was the sale of RDP access for a large clinic group with several branches in the central U.S., which was offered for sale on a Darknet closed forum. For a payment of $50,000 Bitcoins, the buyer would receive access to the compromised workstation, with access to 3 GB of data stored on four hard disks. Additionally, the workstation allows access to an aggregate electronical system (EHR) for managing medical records, where data regarding patients, suppliers, payments and more can be exploited.

Although the seller did not mention the origin of the credentials he was selling, he claimed that local administrator privileges could be received on the compromised system. He also specified that 45 users from the medical personnel were logged into the system from the workstation he hacked.

The relatively high price for this offer indicates the high demand for medical information. With RDP access, the potential attackers can perform any action on the compromised workstation: install malware, encrypt the files or erase them, infect other machines in the network and access any data stored in the network. The consequences can be tremendous.

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An excerpt of the sale thread posted on a Darknet forum

 

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Screenshot allegedly taken on the hacked workstation

Just a few weeks later, in June 2016, our analysts detected another cyber-accident related to healthcare. This time, three databases allegedly stolen via an RDP access to a medical organization were offered for sale for more than $500,000 on a dedicated Darknet marketplace. In one of his posts, the seller claimed that one of the databases belongs to a large American health insurer.

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One of the sales posts on a Darknet marketplace
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Screenshot posted by the seller as a proof of hacking into a medical organization

Before long, we again discovered evidence of hacking into a medical-related organization, this time by Russian-speaking hackers. On one of the forums we monitor, a member tried to sell an SSH access to the server of an American company supplying equipment to 130 medical center in the U.S. He uploaded screenshots proving that he accessed the server where personal data of patients is stored.

The conclusions following these findings are concerning. An extensive trade in medical information and compromised workstations and servers is a common sight on underground illegal markets. This business generates hundreds of thousands, if not millions of dollars annually, ensuring its continuation as long as there are such high profits to those involved. Since the ramifications can be grave, the healthcare sector must take all necessary measures to protect their systems and data:

  1. Implement a strong password policy, because many hacks are a result of brute-force attack. Strong passwords and two-factor authentications to log into organizational systems should be the number one rule for medical organizations.
  2. Deploy suitable security systems.
  3. Instruct the employees to follow cyber security rules – choosing strong and unique passwords, spotting phishing email messages, avoiding clicking on links and downloading files from unknown sources, etc. Consider periodic training for employees on these issues to maintain high awareness and compliance with the rules.
  4. Use Cyber Threat Intelligence (CTI) – to keep up with the times regarding the current most prominent threats to your organization and industry.
  5. Keep all software updated.

New Infographic – Tips on Avoiding Ransomware Attacks

Ransomware is emerging as a predominant online security threat to both home users and businesses, with numerous reports appearing every day on ransomware attacks against organizations across the globe. SenseCy analysts have prepared a short list of security measures recommended for any business to help avoid these attacks. Check out the tips and stay safe!

Defending against Ransomware

Russian Cyber Criminal Underground – 2015: The Prosperity of Ransomware and Office Exploits

The prominent products traded during 2015 on Russian underground forums were Ransomware programs and exploits targeting Microsoft Office. Prices on the Russian Underground have remained unchanged during the past two years, due to the vigorous competition between sellers on these platforms. Different kinds of services, such as digital signing for malicious files, injections development for MitM attacks and Crypting malware to avoid detection were also extremely popular on Russian forums.

Check out the new Infographic from SenseCy illustrating key trends observed on Russian underground in 2015.

Please contact us to receive your complimentary 2015 SenseCy Annual Cyber Threat Intelligence Report: https://www.sensecy.com/contact

Russian_underground_final

Handling a Ransomware Attack

A recent wave of ransomware attacks has hit countries around the world, with a large number of infections reported in the United States, the United Kingdom, Germany and Israel. It appears that the attackers have no specific target, since the attacks have struck hospitals, financial institutions and private institutions, indicating that no specific industry has been targeted.

In Israel, two types of ransomware were identified in the most recent attacks: the familiar TeslaCrypt and the new ransomware, Locky.

The Evolution of Ransomware

The vigorous usage of ransomware tools by cybercriminals and their success in this area has led to the development of new ransomware and the constant upgrading of known models. During the past several months, researchers have reported on the development of ransomware that is capable of file encryption without Internet connection, i.e., they do not communicate with their C&C servers for the encryption process.

New ransomware tools that were reported are Locky ransomware, whose modus operandi resembles the Dridex banking Trojan, and a new version of CTB-Locker that attacks web servers.

Additionally, RaaS (Ransom-as-a-Service) offers are becoming popular on closed DeepWeb and Darknet forums. These services allow potential attackers to easily create ransomware stubs, paying with profits from future successful infections. Recently, we identified a new RaaS dubbed Cerber ransomware, which is offered on a Russian underground forum. Previously it was ORX-Locker, offered as a service via a platform hosted on an .onion server.

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The ransom message presented by the Cerber ransomware

Ransomware Distribution

The majority of the distribution vectors of ransomware stubs involve some kind of social engineering trap, for example, email messages including malicious Office files, spam messages with nasty links or malvertising campaigns exploiting vulnerable WordPress or Joomla websites with an embedded malevolent code. The distribution also takes advantage of Macro commands and exploit kits, such as Nuclear or Angler. Sometimes browser vulnerabilities are exploited, as well as stolen digital certificates.

In November 2015, attempts to deliver ransomware to Israeli clients were identified. In this case, the attackers spoofed a corporate email address and tried to make recipients believe the email was sent from a company worker.

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RaaS offered on a Darknet forum

Handling a Ransomware Attack

Please find below our suggestions for recommended action to avoid ransomware attacks on an organization, and how to deal with an attack after infection:

Defend Your Organization from Potential Threats

  • Train your employees – since the human link is the weakest link in the organizational cybersecurity and the majority of the cases involve social engineering on one of the employees, periodical employee briefing is extremely important. Specify the rules regarding using the company systems, and describe what phishing messages look like.
  • Raise awareness regarding accepting files that arrive via email messages – instruct your employees not to open suspicious files or files sent from unfamiliar senders. Consider implementing an organizational policy addressing such files. We recommend blocking or isolating files with the following extensions: js (JavaScript), jar (Java), bat (Batch file), exe (executable file), cpl (Control Panel), scr (Screensaver), com (COM file) and pif (Program Information file).
  • Disable running of Macro scripts on Office files sent via email – in recent months, many cases of ransomware attacks employing this vector were reported. Usually, Macro commands are disabled by default and we do not recommend enabling them. In addition, we suggest using Office Viewer software to open Word and Excel files.
  • Limit user privileges and constantly monitor the workstations – careful management of user privileges and limited administrator’s privileges may help in avoiding the spread of the ransomware in the organizational network. Moreover, monitoring the activity on workstations will be useful for early detection of any infection and blocking it from propagating to other systems and network resources.
  • Create rules that block programs from executing from AppData/LocalAppData folders. Many variants of the analyzed ransomware are executed from these directories, including CryptoLocker. Therefore, the creation of such rules may reduce the encryption risk significantly.
  • Install a Russian keyboard – while monitoring closed Russian forums where several ransomware families originated, we discovered that many of them will check if the infected computer is located in a post-Soviet country. Usually, this check is performed by detecting which keyboard layout is installed on the machine. If a Russian (or other post-Soviet language) keyboard layout is detected, the ransomware will not initiate the encryption process.
  • Keep your systems updated – in many cases, hackers take advantage of outdated systems to infiltrate the network. Therefore, frequent updates of the organizational systems and implementing the published security patch will significantly reduce the chances of infection.
  • Use third-party dedicated software to deal with the threat – many programs aimed at addressing specific ransomware threats are constantly being released. One is Windows AppLocker, which is included in the OS and assists in dealing with malware. We recommend contacting the organizational security vendor and considering the offered solutions.
  • Implement technical indicator and YARA rules in the company organizations. We provide our clients with intelligence items accompanied by technical indicators. Additionally, a dedicated repository that includes ransomware indicators was launched.
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    A closed forum member looks to blackmail companies using ransomware

    What if I am Already Infected?

  • Restore your files – some ransomware tools create a copy of the file, encrypt it and then erase the original file. If the deletion is performed via the OS erase feature, there is a chance to restore the files, since in majority of the cases, the OS does not immediately overwrite the deleted filed.
  • Decryption of the encrypted files – the decryption will be possible if you were infected by one of these three ransomware types: Bitcryptor, CoinVault or Linux.Encoder.1. Therefore, detecting the exact kind of ransomware that attacked the PC is crucial.
  • Back-up files on a separate storage device regularly – the best practice to avoid damage from a ransomware attack is to backup all your important files on a storage disconnected from the organizational network, since some ransomware variants are capable of encrypting files stored on connected devices. For example, researchers recently reported a ransomware that encrypted files stored on the Cloud Sync folder.
  • If ransomware is detected in the organization, immediately disconnect the infected machine from the network. Do not try to remove the malware or to reboot the system before identifying the ransomware. In some cases, performing one of these actions will make the decryption impossible, even after paying the ransom.