Citrix patches a “nasty bug” in its Application Delivery Management solution that is difficult to exploit.
Background
On June 14, Citrix published a security bulletin (CTX460016) for a pair of vulnerabilities in Citrix Application Delivery Management (ADM), a centralized management solution used to monitor a variety of Citrix networking products.
| CVE | Description | CVSSv3 | VPR* |
|---|---|---|---|
| CVE-2022-27511 | Citrix ADM Improper Access Control Vulnerability | 8.1 | 8.4 |
| CVE-2022-27512 | Citrix ADM Improper Control of a Resource Through its Lifetime Vulnerability | 5.3 | 1.4 |
*Please note: Tenable’sVulnerability Priority Rating(VPR) scores are calculated nightly. This blog post was published on June 17 and reflects VPR at that time.
Analysis
CVE-2022-27511 is an improper access control vulnerability in Citrix ADM. According to Citrix’s advisory, a remote, unauthenticated attacker could exploit this vulnerability to reset the administrator password for the ADM platform following a reboot. Once the exploited device is rebooted, an attacker could connect to the ADM using default administrator credentials, but only if they have SSH access to the device.
CVE-2022-27512 is a vulnerability in Citrix ADM caused by improper control of a resource through its lifetime. A remote, unauthenticated attacker could exploit this flaw to cause a “temporary disruption” of the ADM license service, which would result in the ADM platform being unable to renew existing licenses or issue new ones.
Researchers confirm exploitation is difficult
These vulnerabilities were credited to security researcher Florian Hauser of Code White. According to a tweet from Code White, organizations that have exposed their ADM platform to the internet should apply these patches. However, the tweet also underscores that while the vulnerability is “nasty” it is “hard to exploit.”
If you have #Citrix#ADM exposed, better patch than sorry. @frycos and @CaptnBanana found a hard to exploit but nonetheless nasty bug that could lead to an unauth'ed device brick/takeover: https://t.co/UFP2KKk0fc
— Code White GmbH (@codewhitesec) June 14, 2022
Proof of concept
At the time this blog post was published, no proof-of-concept exploits for either of these flaws was available.
Solution
Citrix has released patches for Citrix ADM Server and Agents. The following table contains a list of affected and fixed versions of Citrix ADM.
| Affected Versions | Fixed Versions |
|---|---|
| 13.1-24.38 and below | 13.1-21.53 and above |
| 13.0-84.10 and below | 13.0-85.19 and above |
Citrix ADM 12.1 is end-of-life and is not receiving support, the advisory does not indicate whether these versions are vulnerable.
In addition to applying these patches, Citrix recommends employing IP address segmentation, which “diminishes the risk of exploitation of these issues.”
Identifying affected systems
A list of Tenable plugins covering both CVEs listed in this blog post can be found here. This link uses a search filter to ensure that all matching plugin coverage will appear as it is released.
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