PoC Exploits Released for Citrix ADC and Gateway RCE Vulnerability
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2019-19781 | Unauthenticated path traversal RCE in Citrix ADC, Gateway, and SD-WAN WANOP CVE-2019-19781 is a path-traversal flaw (classified CWE-22, though CISA's description calls it unspecified) in Citrix ADC (formerly NetScaler ADC), Citrix Gateway, and Citrix SD-WAN WANOP appliances that lets an unauthenticated remote attacker traverse directories via crafted requests and execute arbitrary commands on the appliance, typically with root privileges. It is triggered by sending specially crafted directory-traversal requests (crafted URLs/requests to the appliance's management or VPN endpoints), which lets the attacker write files and run commands with no credentials. Successful exploitation yields arbitrary code execution on the appliance, enabling theft of VPN/ADC credentials, lateral movement into the corporate network, and installation of persistent backdoors. Any organization running affected ADC, Gateway, or SD-WAN WANOP firmware is affected, with internet-facing gateways used for remote access at the highest risk. Exploitation is confirmed in the wild: the vulnerability is on CISA's KEV (added 2021-11-03) with known ransomware use, EPSS assigns near-certain (100.0%) probability of exploitation within 30 days, and no public PoC is listed despite confirmed abuse. Do: Upgrade Citrix ADC, Gateway, and SD-WAN WANOP appliances to the fixed firmware builds listed in Citrix advisory CTX267020; if patching cannot be done immediately, apply Citrix's published interim mitigation and restrict internet exposure to the appliance. Because exploitation grants root code execution and persistence, after patching hunt for indicators of compromise (unexpected nsroot account, modified system files, crontab/scheduled entries), kill all active and inactive sessions, and rotate appliance and VPN credentials. Prioritize internet-facing gateways and comply with CISA's required action to apply vendor updates. | 9.8 | 100% | KEV ransomware |
| massroughly 80,000-100,000+ internet-exposed Citrix ADC/Gateway appliances at the time of disclosure, with a far larger total installed base (including… |
Full article374 words · extracted from thehackernews.com · click to collapse
It's now or never to prevent your enterprise servers running vulnerable versions of Citrix application delivery, load balancing, and Gateway solutions from getting hacked by remote attackers.
Why the urgency? Earlier today, multiple groups publicly released weaponized proof-of-concept exploit code [1, 2] for a recently disclosed remote code execution vulnerability in Citrix's NetScaler ADC and Gateway products that could allow anyone to leverage them to take full control over potential enterprise targets.
Just before the last Christmas and year-end holidays, Citrix announced that its Citrix Application Delivery Controller (ADC) and Citrix Gateway are vulnerable to a critical path traversal flaw (CVE-2019-19781) that could allow an unauthenticated attacker to perform arbitrary code execution on vulnerable servers.
Citrix confirmed that the flaw affects all supported version of the software, including:
- Citrix ADC and Citrix Gateway version 13.0 all supported builds
- Citrix ADC and NetScaler Gateway version 12.1 all supported builds
- Citrix ADC and NetScaler Gateway version 12.0 all supported builds
- Citrix ADC and NetScaler Gateway version 11.1 all supported builds
- Citrix NetScaler ADC and NetScaler Gateway version 10.5 all supported builds
The company made the disclose without releasing any security patches for vulnerable software; instead, Citrix offered mitigation to help administrators guard their servers against potential remote attacks—and even at the time of writing, there's no patch available almost 23 days after disclosure.
Through the cyberattacks against vulnerable servers were first seen in the wild last week when hackers developed private exploit after reverse engineering mitigation information, the public release of weaponized PoC would now make it easier for low-skilled script kiddies to launch cyberattacks against vulnerable organizations.
According to Shodan, at the time of writing, there are over 125,400 Citrix ADC or Gateway servers publicly accessible and can be exploited overnight if not taken offline or protected using available mitigation.
While discussing technical details of the flaw in a blog post published yesterday, MDSsec also released a video demonstration of the exploit they developed but chose not to release it at this moment.
Besides applying the recommended mitigation, Citrix ADC administrators are also advised to monitor their device logs for attacks.
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Text extracted automatically; images, tables and formatting may be missing. Original: https://thehackernews.com/2020/01/citrix-adc-gateway-exploit.html