CVE-2021-44529

CVE-2021-44529: Ivanti EPM Cloud Services Appliance Code Injection

AI-generated analysis based on the vulnerability data on this page.

Summary

CVE-2021-44529 is a code injection vulnerability affecting the Ivanti Endpoint Manager (EPM) Cloud Services Appliance (CSA). An unauthenticated attacker can exploit this flaw to execute arbitrary code on the appliance with limited privileges (as the nobody user).

Background

The Ivanti EPM Cloud Services Appliance is a gateway component designed to bridge on-premises Endpoint Manager instances with cloud-managed endpoints. It handles external requests and proxies management traffic. Because it sits at the perimeter and processes untrusted input, flaws in its input validation can have immediate network-exploitable consequences.

Root Cause

The vulnerability is classified under CWE-94: Improper Control of Generation of Code ('Code Injection'). The CSA fails to adequately sanitize user-supplied input before incorporating it into code or command execution paths. This allows an external, unauthenticated attacker to inject and execute arbitrary instructions on the host appliance.

Impact

The NVD assigns this vulnerability a CVSS 3.1 score of 9.8 (Critical). The vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H reflects:

• Network attack vector — exploitable remotely without local access.
• Low attack complexity — no special conditions or advanced techniques needed.
• No privileges required — fully unauthenticated.
• No user interaction — can be exploited without tricking a legitimate user.
• High impact across confidentiality, integrity, and availability.

While the executed code runs under the nobody account, the appliance typically hosts sensitive management traffic and credential material, making privilege escalation a realistic secondary concern.

Exploitation Walkthrough

From a defensive perspective, exploitation is understood to proceed as follows:

1. The attacker sends a crafted HTTP request to the CSA containing malicious input within a parameter or header field processed by the appliance.
2. The unsanitized input reaches a backend function that evaluates or executes the data as code.
3. The attacker gains remote execution as the nobody user.

Ethics caveat: This description is based on public vulnerability metadata and advisory summaries. No step-by-step exploit code is provided here. Defenders should prioritize patching and detection over reproducing the attack.

Affected and Patched Versions

• Affected product: Ivanti Endpoint Manager Cloud Services Appliance (CSA)
• Affected version: 4.6 and prior versions (based on CPE data)
• Patched version: See Ivanti security advisory SA-2021-12-02

Remediation

1. Upgrade immediately: Apply the patch referenced in Ivanti Security Advisory SA-2021-12-02. Because this CVE is on the CISA Known Exploited Vulnerabilities (KEV) catalog, patching should be treated as an emergency change.
2. Compensating controls: If immediate patching is not feasible, restrict inbound access to the CSA to trusted administrative IP ranges via firewall rules or VPN gating. Disable or decommission unused CSA instances.
3. Network segmentation: Place the CSA in a tightly controlled DMZ with strict egress filtering to limit lateral movement in the event of compromise.

Detection

• Monitor appliance logs for anomalous HTTP requests containing unexpected characters, encoded payloads, or oversized fields in parameters processed by the CSA.
• Alert on process execution from the CSA web service context (e.g., nobody spawning unexpected shells or interpreters).
• Correlate CSA access logs with threat intelligence feeds referencing known exploitation patterns for this CVE.
• Given the EPSS of 0.99105 (99.1% probability of exploitation), prioritize scanning for this vulnerability in external attack-surface assessments.

Assessment

This vulnerability is actively exploited in the wild, as confirmed by its inclusion in the CISA KEV catalog (added 2024-03-25) and its exceptionally high EPSS score of 0.99105 (99.28th percentile). The combination of unauthenticated remote access, low attack complexity, and critical impact makes it a textbook high-priority remediation target.

Key lessons:

• Perimeter appliances that bridge internal management infrastructure to the internet must be subject to rigorous input validation and secure coding practices.
• The lag between original disclosure (December 2021) and KEV listing (March 2024) illustrates that even older vulnerabilities can become actively exploited over time; continuous vulnerability scanning and patch hygiene are essential.

References

• Ivanti Security Advisory SA-2021-12-02
• CISA KEV Catalog Entry
• Packet Storm - Ivanti EPM CSA 4.5/4.6 Remote Code Execution
• Packet Storm - Ivanti CSA Command Injection