{"uuid": "057490a3-7cf1-46d9-919f-f6c0ed33283d", "vulnerability_lookup_origin": "1a89b78e-f703-45f3-bb86-59eb712668bd", "author": "9f56dd64-161d-43a6-b9c3-555944290a09", "vulnerability": "CVE-2020-3992", "type": "seen", "source": "https://t.me/hacking_Attack/80218", "content": "Black Hat Ethical Hacking\nNew Python malware backdoors VMware ESXi servers for remote access\n\nNew Python malware backdoors VMware ESXi servers for remote accessPost Views: 78 Premium Contenthttps://www.blackhatethicalhacking.com/wp-content/uploads/2022/12/Patreon.png Subscribe to Patreon to watch this episode.\nReading Time: 3 Minutes A previously undocumented Python backdoor targeting VMware ESXi servers has been spotted, enabling hackers to execute commands remotely on a compromised system.VMware ESXi is a virtualization platform commonly used in the enterprise to host numerous servers on one device while using CPU and memory resources more effectively.\n\nThe new backdoor was discovered by Juniper Networks researchers, who found the backdoor on a VMware ESXi server. However, they could not determine how the server was compromised due to limited log retention.\n\nThey believe the server may have been compromised using the CVE-2019-5544 and CVE-2020-3992 vulnerabilities in ESXi\u2019s OpenSLP service.\n\nWhile the malware is technically capable of targeting Linux and Unix systems, too, Juniper\u2019s analysts found multiple indications it was designed for attacks against ESXi.\nSee Also: So you want to be a hacker? Complete Offensive Security and Ethical Hacking Course Backdoor operationThe new python backdoor adds seven lines inside \u201c/etc/rc.local.d/local.sh,\u201d one of the few ESXi files that survive between reboots and is executed at startup.\n\nUsually, that file is empty, apart from some advisory comments and an exit statement.\nhttps://www.bleepstatic.com/images/news/u/1220909/Code%20and%20Details/lines.png \n<figcaptionAdditional lines added on ESXi file (Juniper Networks) \nOne of those lines launches a Python script saved as \u201c/store/packages/vmtools.py,\u201d in a directory that stores VM disk images, logs, and more.\n\nThe script\u2019s name and location make Juniper Networks believe that the malware operators intend to target VMware ESXi servers specifically.\n\n\u201cWhile the Python script used in this attack is cross-platform and can be used with little or no modification on Linux or other UNIX-like systems, there are several indications that this attack was designed specifically to target ESXi,\u201d explains Juniper Networks\u2019 report.\n\n\u201cThe name of the file and its location, /store/packages/vmtools.py, was chosen to raise little suspicion on a virtualization host.\u201d\n\n\u201cThe file begins with a VMware copyright consistent with publicly available \u00a0 examples and is taken character-for-character from an existing Python file provided by VMware.\u201d\n\nThis script launches a web server that accepts password-protected POST requests from the remote threat actors. These requests can carry a base-64 encoded command payload or launch a reverse shell on the host.\n\nThe reverse shell makes the compromised server initiate the connection with the threat actor, a technique that often helps bypass firewall restrictions or works around limited network connectivity.\n\nOne of the threat actors\u2019 actions observed by Juniper\u2019s analysts was to change the ESXi reverse HTTP proxy configuration to allow remote access to communicate with the planted webserver.\n\nBecause the file used for setting this new configuration, \u201c/etc/vmware/rhttpproxy/endpoints.conf,\u201d is also backed up and restored after reboot, any modifications on it are persistent.\nTrending: Exploit XSS Injections in a one-line powerful Technique Trending: Offensive Security Tool: Pycrypt \u200bMitigatingTo determine if this backdoor has impacted your ESXi servers, check for the existence of the files mentioned above and the additional lines in the \u201clocal.sh\u201d file.\n\nAll configuration files that persist reboots should be scrutinized for suspicious changes and reversed to the correct [...]", "creation_timestamp": "2026-09-01T20:01:14.055367Z"}