CVE-2025-49827: CyberArk Conjur Auth Bypass Vulnerability

CVE-2025-49827 Overview

CVE-2025-49827 is a critical authentication bypass vulnerability affecting CyberArk Conjur, a secrets management and application identity platform for infrastructure. The vulnerability exists in the IAM authenticator component, where an attacker who can manipulate AWS-signed headers can exploit a malformed regular expression to redirect authentication validation requests to a malicious server under their control. This redirection enables complete bypass of the IAM Authenticator, allowing attackers to assume the permissions of legitimate clients whose requests were manipulated.

Critical Impact

Successful exploitation allows attackers to bypass IAM authentication and gain unauthorized access to secrets and credentials managed by Conjur, potentially compromising entire infrastructure security postures.

Affected Products

• CyberArk Conjur OSS versions 1.19.5 through 1.22.0
• CyberArk Secrets Manager, Self-Hosted (formerly Conjur Enterprise) versions 13.1 through 13.5
• CyberArk Secrets Manager, Self-Hosted version 13.6

Discovery Timeline

• 2025-07-15 - CVE-2025-49827 published to NVD
• 2025-11-04 - Last updated in NVD database

Technical Details for CVE-2025-49827

Vulnerability Analysis

This vulnerability (CWE-807: Reliance on Untrusted Inputs in a Security Decision) stems from improper validation of authentication requests within the Conjur IAM authenticator. The core issue lies in a malformed regular expression used to validate AWS authentication endpoints. When Conjur receives an authentication request with AWS-signed headers, it validates these credentials by sending a request to AWS Security Token Service (STS). However, the flawed regex pattern allows attackers to craft headers that redirect this validation request to an attacker-controlled server instead of legitimate AWS infrastructure.

The attack exploits the trust relationship between Conjur and AWS STS. By manipulating the signed headers in a way that passes the malformed regex validation but points to a different endpoint, attackers can respond to the validation request with a forged successful authentication response. This effectively bypasses the entire IAM authentication mechanism without requiring valid AWS credentials.

Root Cause

The root cause is a malformed regular expression in the IAM authenticator code that fails to properly validate the AWS STS endpoint URL. The regex pattern does not adequately constrain the allowed characters or format of the endpoint, enabling attackers to inject alternative hostnames that satisfy the regex while pointing to malicious infrastructure. This represents a fundamental failure in input validation for a security-critical component.

Attack Vector

The attack is network-based and requires no authentication or user interaction. An attacker must be able to intercept or craft authentication requests to the Conjur server. The attack flow proceeds as follows:

1. The attacker crafts a malicious authentication request with manipulated AWS-signed headers
2. The headers contain a modified endpoint URL that satisfies the flawed regex pattern
3. Conjur's IAM authenticator accepts the headers and attempts validation
4. The validation request is redirected to the attacker's server instead of AWS STS
5. The attacker's server responds with a forged successful validation response
6. Conjur grants the attacker the permissions of the impersonated client

The vulnerability allows network-based exploitation without prior authentication. An attacker who successfully exploits this flaw gains the ability to read sensitive secrets and manipulate identity data, effectively compromising the confidentiality and integrity of the secrets management infrastructure.

Detection Methods for CVE-2025-49827

Indicators of Compromise

• Unusual authentication validation requests to non-AWS IP addresses or domains
• Authentication successes from AWS IAM roles that should not have access to specific secrets
• Anomalous STS endpoint URLs in Conjur audit logs containing unexpected hostnames
• Discrepancies between AWS CloudTrail logs and Conjur authentication events

Detection Strategies

• Monitor Conjur audit logs for IAM authentication events with unusual source characteristics
• Implement network monitoring to detect outbound validation requests to non-AWS endpoints
• Correlate Conjur authentication logs with AWS CloudTrail to identify phantom authentications
• Deploy network segmentation rules to restrict Conjur's outbound connections to legitimate AWS STS endpoints only

Monitoring Recommendations

• Enable verbose logging on Conjur instances to capture full authentication request details
• Configure alerts for authentication validation requests to IP ranges outside AWS
• Implement anomaly detection for unusual patterns in IAM authenticator activity
• Review secrets access patterns for unexpected role-based retrievals

How to Mitigate CVE-2025-49827

Immediate Actions Required

• Upgrade Conjur OSS to version 1.22.1 or later immediately
• Upgrade Secrets Manager, Self-Hosted to version 13.5.1 or 13.6.1 depending on your current major version
• Audit recent authentication logs for signs of exploitation before patching
• Rotate any secrets that may have been accessed by suspicious authentications

Patch Information

CyberArk has released patched versions that correct the malformed regular expression in the IAM authenticator. The following versions contain the fix:

• Conjur OSS: Version 1.22.1 - available via GitHub Conjur Release v1.22.1
• Secrets Manager, Self-Hosted: Versions 13.5.1 and 13.6.1

For detailed information about the vulnerability and remediation, refer to the GitHub Security Advisory GHSA-gmc5-9mpc-xg75.

Workarounds

• Implement network-level restrictions to ensure Conjur can only communicate with legitimate AWS STS endpoints
• Deploy a web application firewall or proxy to inspect and validate outbound authentication requests
• Consider temporarily disabling the IAM authenticator if alternative authentication methods are available
• Use IP allowlisting to restrict which sources can send authentication requests to Conjur

# Example: Restrict outbound connections to AWS STS endpoints only
# Add to firewall rules (iptables example)
iptables -A OUTPUT -p tcp -d sts.amazonaws.com --dport 443 -j ACCEPT
iptables -A OUTPUT -p tcp -d sts.*.amazonaws.com --dport 443 -j ACCEPT
iptables -A OUTPUT -p tcp --dport 443 -m owner --uid-owner conjur -j DROP