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  • Using DNS to weaken Locky ransomware threat

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    Ransomware and other cyberthreats often go unseen by traditional detection methods like antivirus, deep packet inspection (DPI) or sandboxing. In fact, a report by Lastline Labs indicates that 51% of zero-day malware—threats that strike before developers have time to release a patch—is undetected by anti-virus solutions. So what can security professionals do to stop attacks? The answer lies, in part, in DNS.

    One of the most powerful ransomware threats currently targeting individuals and organizations is Locky, which infects up to 100,000 devices per day, of which 3% submit payments. Cybersecurity experts estimate that Locky possesses 17% of the entire global market share for all ransomware infections.

    First, let’s look at a few statistics that demonstrate the power and expense of Locky:

    Locky is typically delivered through aggressive spam campaigns, often claiming to be an invoice. Despite the known dangers of clicking on links in unknown emails, Locky is so sly it entices even trained IT staff to click on obscure messages and activate downloads.

    Once a download has completed, Locky connects with its Command & Control (C&C) server to get a cryptographic key to use for encryption. There are three known mechanisms for Locky to reach its C&C hosts:

    1. Direct IP communication
    2. A number of fixed domains
    3. A time-based Domain Generation Algorithm (DGA) that creates a set of random-looking domains that are only valid for a few days

    Here is where DNS can play a role. DNS data can be analyzed to identify C&C connection mechanisms. When these communications are blocked, Locky’s ability to obtain encryption keys is limited, giving infected users a better chance of being protected.

    Unfortunately, the DGA used by Locky to generate domains and get encryption keys is marked with the current time period combined with a secret seed, making it harder to block new domains quickly. Locky changes seeds frequently, and reverse engineering current versions of the malware to discover each new seed takes time. Every new seed indicates another wave in the life of the exploit, so until there is an accurate way to identify traffic associated with Locky, it can’t be permanently blocked.

    But examination of a worldwide feed of anonymized DNS queries, along with anomaly detection and correlation technology, makes it possible to identify suspected domains used by Locky to download encryption keys in real time. ForcePoint is one company that has done some work to reverse engineer the DGA used by Locky. By using the existing DGA and conducting some additional processing of suspect domains, it is possible to determine new seeds used by Locky, thereby enumerating all future new domains Locky will use.

    Below is a sampling of more recent domains created by Locky as detected by our DNS algorithms:

    • mrjuvawlwa[.]xyz
    • uydvrqwgg[.]su
    • uwiyklntlxpxj[.]work
    • owvtbqledaraqq[.]su
    • udfaexci[.]ru
    • eabfhwl[.]ru
    • olyedawaki[.]pl
    • uxwfukfqxhydqawmf[.]su
    • ikdcjjcyjtpsc[.]work
    • wrbwtvcv[.]su
    • osxbymbjwuotd[.]click
    • qtuanjdpx[.]info

    As Locky and other types of ransomware become more adept at avoiding detection and remediation, new strategies need to be used to combat them. Many of the new cyberthreat strategies make traditional malware block lists less effective. Facing DGAs with fast-changing seeds, security researchers must constantly identify the new seeds used by each wave of phishing to pre-generate domains. Once new seeds are released the old ones immediately become obsolete.

    By utilizing a broad set of DNS query data, it is possible to detect and track the evolution of generated domains through a variety of algorithmic methods such as clustering, reputation scoring, reverse engineering and additional methods that continuously evolve. Recent innovations include anomaly detection algorithms, new domain clustering and a Domain Reputation System that resulted in almost 100,000 domains and C&Cs provisioned daily for blocking.

    By employing these advanced methods, suspicious domains can be detected with a high level of accuracy very quickly, and false positives can also be weeded out so good traffic can still reach legitimate sites. Currently, this is the best defense against Locky. Service providers and companies can use this technique to protect their online users from having their files encrypted, and identify machines that have been infected.

    Locky provides ample evidence that attackers are continuously innovating. Staying one step ahead requires cybersecurity expertise and real-time processing of massive, worldwide data sets to uncover malicious activity. Blocking traffic to these domains is a good way to avoid the threat of Locky, and expert security teams that take the right steps to understand its behavior and put appropriate measures in place to protect would-be victims will render cyberthreats much less effective.


    📂This entry was posted in Computer News Virus Threats 📎and tagged

  • First Android Phone Ransomware that Encrypts your SD card Files

    Posted on by admin Comment
    We have seen cybercriminals targeting PCs with Ransomware malware that encrypts your files or lock down your computer and ask for a ransom amount to be paid in a specified duration of time to unlock it.
    To deliver the Ransomware malwares to the mobile devices, cyber criminals have already started creating malicious software programs for android devices. Last month, we reported about a new Police Ransomware malware that locks up the devices until the victims pay a ransom to get the keys to unlock the phone. But, the malware just lock the mobile screen and a loophole in the its implementation allowed users to recover their device and data stored on SDcard.

    Now, in an effort to overcome this, threat actors have adopted encryption in the development of mobile Ransomware malwares. Recently, the security firm ESET has discovered a new Android ransomware, dubbed as Android/Simplocker.A, that has ability to encrypt the files on the device SD card and then demand a ransom from the victim in order to decrypt those files.

    Once installed, the malware scans the SD card for certain file types such as image, document or video with extensions – jpeg, jpg, png, bmp, gif, pdf, doc, docx, txt, avi, mkv, 3gp, mp4 and encrypts them using AES in a separate thread in the background. After encrypting the files, the malware displays the following ransom message, written in Russian, which clearly means that this threat is targeting Russian Android users.

    “WARNING your phone is locked!
    The device is locked for viewing and distributing child pornography , zoophilia and other perversions.
    To unlock you need to pay 260 UAH.
    1.) Locate the nearest payment kiosk.
    2.) Select MoneXy
    3.) Enter {REDACTED}.
    4.) Make deposit of 260 Hryvnia, and then press pay. Do not forget to take a receipt!
    After payment your device will be unlocked within 24 hours. In case of no PAYMENT YOU WILL LOSE ALL DATA ON your device!”

    The Ransomware malware directs victim to pay the ransom amount i.e. 260 UAH, which is roughly equal to $21 US, through the MoneXy service, as this payment service is not easily traceable as the regular credit card.

    mobile virus

    To maintain anonymity the malware author is using the Command-and-Control server hosted on TOR .onion domain and the malware sends the information of the infected device such as IMEI number to its server. The researchers at ESET are still analysing the malware:

    “Our analysis of the Android/Simplock.A sample revealed that we are most likely dealing with a proof-of-concept or a work in progress – for example, the implementation of the encryption doesn’t come close to “the infamous Cryptolocker” on Windows.”

    The researchers have found that the malware is capable to encrypt the victim’s files, which could be lost if the decryption key is not retrieved from the malware author by paying the ransom amount, but on the other hand the researchers strongly advise users against paying fine, as their is no guarantee that the hacker will provide you decryption keys even after paying the amount.
    Unfortunately, mobile antivirus products are only capable to detect such known/detected threats only and can’t detect similar the new threats. So, it is important for you to always keep the back-up of all your files either manually on the computer system or use cloud backup services like dropbox, google drive etc, in order to protect it from the emerging threats.

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    📂This entry was posted in Virus Threats 📎and tagged