Schließen
Schließen
Ihr Netzwerk von morgen
Ihr Netzwerk von morgen
Planen Sie Ihren Weg zu einem schnelleren, sichereren und widerstandsfähigeren Netzwerk, das auf die von Ihnen unterstützten Anwendungen und Benutzer zugeschnitten ist.
          Erleben Sie Netskope
          Get Hands-on With the Netskope Platform
          Here's your chance to experience the Netskope One single-cloud platform first-hand. Sign up for self-paced, hands-on labs, join us for monthly live product demos, take a free test drive of Netskope Private Access, or join us for a live, instructor-led workshops.
            Ein führendes Unternehmen im Bereich SSE. Jetzt ein führender Anbieter von SASE.
            Ein führendes Unternehmen im Bereich SSE. Jetzt ein führender Anbieter von SASE.
            Netskope debütiert als Leader im Gartner ® Magic Quadrant ™ für Single-Vendor SASE
              Generative KI für Dummies sichern
              Generative KI für Dummies sichern
              Learn how your organization can balance the innovative potential of generative AI with robust data security practices.
                Modern data loss prevention (DLP) for Dummies eBook
                Moderne Data Loss Prevention (DLP) für Dummies
                Get tips and tricks for transitioning to a cloud-delivered DLP.
                  Modernes SD-WAN für SASE Dummies-Buch
                  Modern SD-WAN for SASE Dummies
                  Hören Sie auf, mit Ihrer Netzwerkarchitektur Schritt zu halten
                    Verstehen, wo die Risiken liegen
                    Advanced Analytics transforms the way security operations teams apply data-driven insights to implement better policies. With Advanced Analytics, you can identify trends, zero in on areas of concern and use the data to take action.
                        Die 6 überzeugendsten Anwendungsfälle für den vollständigen Ersatz älterer VPNs
                        Die 6 überzeugendsten Anwendungsfälle für den vollständigen Ersatz älterer VPNs
                        Netskope One Private Access is the only solution that allows you to retire your VPN for good.
                          Colgate-Palmolive schützt sein "geistiges Eigentum" mit intelligentem und anpassungsfähigem Datenschutz
                          Colgate-Palmolive schützt sein "geistiges Eigentum" mit intelligentem und anpassungsfähigem Datenschutz
                            Netskope GovCloud
                            Netskope erhält die FedRAMP High Authorization
                            Wählen Sie Netskope GovCloud, um die Transformation Ihrer Agentur zu beschleunigen.
                              Let's Do Great Things Together
                              Die partnerorientierte Markteinführungsstrategie von Netskope ermöglicht es unseren Partnern, ihr Wachstum und ihre Rentabilität zu maximieren und gleichzeitig die Unternehmenssicherheit an neue Anforderungen anzupassen.
                                Netskope solutions
                                Netskope Cloud Exchange
                                Netskope Cloud Exchange (CE) provides customers with powerful integration tools to leverage investments across their security posture.
                                  Technischer Support von Netskope
                                  Technischer Support von Netskope
                                  Überall auf der Welt sorgen unsere qualifizierten Support-Ingenieure mit verschiedensten Erfahrungen in den Bereichen Cloud-Sicherheit, Netzwerke, Virtualisierung, Content Delivery und Software-Entwicklung für zeitnahen und qualitativ hochwertigen technischen Support.
                                    Netskope-Video
                                    Netskope-Schulung
                                    Netskope-Schulungen helfen Ihnen, ein Experte für Cloud-Sicherheit zu werden. Wir sind hier, um Ihnen zu helfen, Ihre digitale Transformation abzusichern und das Beste aus Ihrer Cloud, dem Web und Ihren privaten Anwendungen zu machen.

                                      Coin mining malware heads to the cloud with Zminer

                                      Aug 24 2017
                                      Tags
                                      Bitcoin
                                      CASB
                                      Cloud Access Security Broker
                                      Cloud Security
                                      coin mining
                                      Data Loss Prevention Software

                                      Netskope Threat Research Labs has detected several samples related to a coin miner malware named Zminer. The kill chain begins with the delivery of a drive-by download Zminer executable that downloads payloads from Amazon S3 cloud storage to a victim’s machine and then uses the machine’s computing resources to perform coin mining. Netskope Threat Research Labs detects the parent file as Gen:trojan.her.jp.iuw@acephpni and the downloaded payloads as Backdoor.generckd.12153334, Backdoor.generckd.5229808 and Application.BitCoinMiner.RH

                                      Overview

                                      “Coin mining” is a term that became popular after the introduction of Bitcoin. Bitcoin is the first decentralized digital currency invented by a programmer named Satoshi Nakamoto. It does not make use of financial institutions as it is solely tied to the Bitcoin addresses, so no central authority is necessary to control the currency. Transactions are made by digitally exchanging encrypted hash codes across a peer-to-peer (P2P) network between users. Each user’s bitcoins are stored in a program called a digital wallet, which also holds the user’s address for sending and receiving bitcoins and a private key only known to the user as an additional layer of protection. There are several coins similar to Bitcoin that we will explain in the cryptocurrencies section

                                      Coin Mining

                                      Coin mining is a procedure for earning coins by mining hardware based on a fixed amount of computing power. This is performed using a coin miner. Anyone with access to the internet and suitable hardware can participate in mining. Depending on the hardware and resources available, several mining methods like CPU mining, GPU mining, FPGA mining, ASC mining and cloud mining are used for coin mining. Upon verification of these mining transactions, a coin is generated using a public ledger, known as the blockchain.

                                      Mining coins using standard computer hardware has become unprofitable. Pooled mining approach has been introduced to compensate this problem. Pooled mining is a mining approach where groups of individual miners contribute to the generation of a block, and then split the block reward according to the contributed processing power. A comprehensive list of some of the pools and their payout methods are documented in this Wikipedia article.

                                      Cryptocurrency

                                      A cryptocurrency works as a digital asset exchange medium using cryptography. Bitcoin is the first decentralized cryptocurrency, which has led to the creation of several cryptocurrencies. There are more than 900 cryptocurrencies as of 11 July 2017 documented in Wikipedia.

                                      Cryptocurrency Valuation

                                      Cryptocurrencies have a market cap of nearly $150 billion with Bitcoin taking the top spot. Currently valued around $4,000 per bitcoin and on a fast pace towards the $5,000 per bitcoin valuation, the chart of Bitcoin’s value is shown in Figure 1.

                                      Figure 1: Bitcoin Price Chart

                                      Cybercriminals and Cryptocurrency

                                      The massive growth of the internet as a money model for cryptocurrencies has attracted the interest of cybercriminals. Malware is implanted in a victim’s machine to perform the following:

                                      • Mine bitcoins using the machine’s computing resources or even a company’s server power
                                      • Steal the victim’s Bitcoin wallet
                                      • Pay ransom using Bitcoin to recover the ransomware-encrypted files

                                      Analysis of Zminer

                                      On execution, Zminer downloads two payloads from Amazon S3 Cloud storage named Claymore+CryptoNote+CPU+Miner+v3.5+Beta+-+POOL.zip and Manager.exe as shown in Figure 2 and Figure 3.

                                      Figure 2: Claymore CryptoNote CPU Miner payload from Amazon S3 Cloud Storage

                                      Figure 3: Manager.exe payload from Amazon S3 Cloud Storage

                                      Analysis of the payloads

                                      NsCpuCNMiner32.exe

                                      NsCpuCNMiner32.exe is a Monero (XMR) CPU miner executable dropped in the %Application Data%\Claymore CryptoNote CPU Miner v3.5 Beta – POOL\ directory. Monero (XMR) is an open-source cryptocurrency that uses the CryptoNote technology. This makes anyone with a computer able to mine it with a simple processor. The hashing power can be distributed throughout an entire network as long as the mining is within a small/medium pool. The Monero (XMR) CPU miner executable is a command line application that has several functions as shown in Figure 4.

                                      Figure 4: Monero (XMR) CPU miner executable options

                                      Manager.exe

                                      Manager.exe ensures that Zminer will be able to carry out the mining operation. This is dropped in %windir% on installation. The binary contains an encrypted string that is decrypted during runtime as shown in Figure 5.

                                      Figure 5: Decrypted Amazon S3 URL with the payload

                                      The decrypted string is a URL that downloads another binary named DBupdater.exe using Amazon S3 cloud storage. The packet capture of the download activity is shown in Figure 6.

                                      Figure 6: DBupdater.exe payload from Amazon S3 cloud storage

                                      DBUpdater.exe

                                      DBupdater.exe creates a log file named log.txt, that contains several details of the victim’s machine. The file is then uploaded to the C&C server with IP 54.214.246[.]97. The IP is registered to Amazon S3 whose resolve host is ec2-54-214-246-97.us-west-2.compute[.]amazonaws.com. The packet capture of the download activity is shown in Figure 7.

                                      Figure 7: Data uploaded to the C&C 54.214.246[.]97

                                      The log.txt file is deleted once the data is uploaded to the C&C

                                      Driver.job, Manager.job

                                      Driver.job and Manager.job job files contain instructions for the Windows Task Scheduler to execute. These are dropped in %windir%\Tasks\ folder and is only created in Windows XP. An example of the job file created by driver.job is shown in Figure 8.

                                      Figure 8: %windir%\Tasks\Driver.job

                                      Zminer in operation

                                      Once the required components are downloaded and installed in the victim’s machine, Zminer begins the mining operation.

                                      To ensure smooth functionality, Zminer disables the inbuilt Windows Defender security service by adding keys in the registry as shown in Figure 9.

                                      Figure 9:  Zminer disabling Windows Defender

                                      The mining is performed using the Nanopool “stratum+tcp://xmr-eu1.nanopool.org” in the victim’s machine with a user address that is hardcoded in the binary which is run via command line as shown in Figure 10.

                                      Figure 10:  Nanopool mining details using stratum+tcp://xmr-eu1.nanopool.org

                                      The packet capture of the mining operation is shown in Figure 11.

                                      Figure 11:  Details of the mining operation

                                      We accessed the website,  https://xmr.nanopool.org/blocks and found the details of the user address hard coded in the binary. The details of the user address are shown in Figure 12.

                                      Figure 12: Details of the user address hard coded in the binary

                                      At the time of writing, the user address has been paid 101.736078074478 XMR. XMR is the code for Monero. It is currently valued close to 80 USD per XMR.

                                      Depending on the operating system, Zminer downloads a version of nheqminer for a 64 bit Windows machine using Amazon S3 Cloud Storage as shown in Figure 13.

                                      Figure 13: Nheqminer payload from Amazon S3 Cloud Storage

                                      The mining is performed using the Nanopool “zec-eu1.nanopool.org” in the victim’s machine with a user address that is hard coded in the binary which is run via command line as shown in Figure 14.

                                      Figure 14: Nanopool mining details using zec-eu1.nanopool.org

                                      We accessed the website, https://zec-bitcore1.trezor.io  and found out details of the other user address hard coded in the binary. The details of the user address are shown in Figure 15.

                                      Figure 15: Details of the other user address hard coded in the binary

                                      At the time of writing, the other user address has been paid 44.12392799 ZEC. ZEC is the code for Zcash. It is currently valued close to 31 USD per ZEC.

                                      Since the mining operation usually involves a lot of computing power, the CPU usage will be extensively dominated by the miner. As a result, the machines or workstations start functioning abnormally slow. An example of the CPU utilization with Zminer using NsCpuCNMiner is shown in Figure 16.

                                      Figure 16: Zminer hogging CPU usage

                                      Similar Zminer Strains

                                      During our research, we identified similar strains of Zminer. While investigating the samples, one of the sample detected by Netskope Threat Protection as Backdoor.generckd.5229808 had the email address mentioned in the mining operation as shown in Figure 17.

                                      Figure 17: Possible email address associated with the mining operation

                                      Conclusion

                                      The extensive adoption of cryptocurrency for purchases and trading has attracted the attention of cybercriminals. Since a crypto mining operation involves a lot of computing power and resources, cyber criminals implant miners in the victims’ machines to generate revenue. These attacks can be effectively carried out in a corporate environment as the machines and workstations have good hardware with abundant supply of electricity. This can lead to severe consequences as the corporate resources and data used for performing a coin mining operation can be used for any cybercriminal or illegal action. Though Bitcoin is considered illegal in several countries, the use of coin miners in a corporate instance is potentially unsafe. Organizations should have policies to detect the presence of bitcoins and mining pools. As enterprises are rapidly adopting the use of Cloud and Cloud services, the need for a threat-aware solution and defensive mechanism for SSL inspection is required. Netskope has disclosed to Amazon S3 cloud storage about the URLs hosting the Zminer payloads.

                                      General Recommendations

                                      Netskope recommends the following to combat cloud malware and threats:

                                      • Detect and remediate cloud threats using a threat-aware cloud access security broker like Netskope and enforce policy on usage of unsanctioned services as well as unsanctioned instances of sanctioned cloud services
                                      • Sample policies to enforce:
                                        • Scan all uploads from unmanaged devices to sanctioned cloud applications for malware
                                        • Scan all uploads from remote devices to sanctioned cloud applications for malware
                                        • Scan all downloads from unsanctioned cloud applications for malware
                                        • Scan all downloads from unsanctioned instances of sanctioned cloud applications for malware
                                        • Enforce quarantine/block actions on malware detection to reduce user impact
                                        • Block unsanctioned instances of sanctioned/well known cloud apps, to prevent attackers from exploiting user trust in cloud. While this seems a little restrictive, it significantly reduces the risk of malware infiltration attempts via cloud
                                      • Enforce DLP policies to control files and data en route to or from your corporate environment
                                      • Regularly back up and turn on versioning for critical content in cloud services
                                      • Enable the “View known file extensions” option on Windows machines
                                      • Warn users to avoid executing unsigned macros and macros from an untrusted source, unless they are very sure that they are benign
                                      • Administrators can create firewall rules to block bitcoin pools documented in the Wikipedia article
                                      • Warn users to avoid executing any file unless they are very sure that they are benign
                                      • Warn users against opening untrusted attachments, regardless of their extensions or filenames
                                      • Keep systems and antivirus tools updated with the latest releases and patches
                                      author image
                                      Ashwin Vamshi
                                      Ashwin Vamshi is a Security Researcher with innate interest in targeted attacks and malwares using cloud services.
                                      Ashwin Vamshi is a Security Researcher with innate interest in targeted attacks and malwares using cloud services.

                                      Bleiben Sie informiert!

                                      Abonnieren Sie den Netskope-Blog