CVE-2025-56689 identifies a vulnerability in One Identity by Quest Safeguard for Privileged Passwords Appliance version 7.5.1.20903. The issue concerns the bypass of One Time Password (OTP) or Multifactor Authentication (MFA) mechanisms through response manipulation. Specifically, an attacker who intercepts or captures a valid OTP response can replay this response to bypass the OTP verification step, effectively circumventing the second factor of authentication. The vulnerability arises because the product authenticates clients based on possession of a cookie whose validity interval includes the current time. This cookie, which has the HttpOnly attribute to prevent client-side script access, is used as a token to confirm authentication status. The supplier disputes that this constitutes a security violation, arguing that the design intentionally allows authentication for clients possessing a valid cookie within its time window, and thus replaying the OTP response is not considered a breach of the security model. The vulnerability is categorized under CWE-290 (Authentication Bypass by Spoofing) and has a CVSS v3.1 base score of 4.6 (medium severity), with vector metrics indicating network attack vector (AV:N), low attack complexity (AC:L), requiring privileges (PR:L), user interaction (UI:R), unchanged scope (S:U), low confidentiality impact (C:L), no integrity impact (I:N), and low availability impact (A:L). No known exploits are reported in the wild, and no patches are currently linked. The vulnerability highlights a design trade-off where possession of a valid authentication cookie within its time validity window can be leveraged by an attacker who intercepts OTP responses, potentially enabling unauthorized access to privileged password management functions.

For European organizations, this vulnerability poses a risk to the security of privileged account management systems, which are critical for controlling access to sensitive infrastructure and data. Successful exploitation could allow attackers to bypass MFA protections, undermining a key security control designed to prevent unauthorized access. This could lead to unauthorized retrieval or manipulation of privileged credentials, increasing the risk of lateral movement, data breaches, or disruption of critical services. The impact on confidentiality is low to medium since the attacker gains access to privileged password management functions, but integrity impact is minimal as the vulnerability does not directly allow modification of data. Availability impact is also low but could increase if attackers misuse privileged credentials to disrupt services. The requirement for user interaction and privileges limits the ease of exploitation, reducing the likelihood of widespread attacks. However, organizations relying heavily on this appliance for privileged access management should consider the risk significant due to the critical nature of the protected assets. The dispute by the vendor regarding the vulnerability's classification suggests that the risk may be mitigated by the product's intended security model, but organizations should carefully evaluate their threat model and exposure to interception attacks, especially in environments where network traffic could be monitored or captured by adversaries.

To mitigate this vulnerability, European organizations should implement the following specific measures: 1) Enforce strict network segmentation and encryption (e.g., TLS 1.3) to prevent interception or capture of OTP responses and authentication cookies. 2) Monitor and restrict access to the Safeguard appliance to trusted networks and devices, minimizing exposure to interception threats. 3) Implement short validity intervals for authentication cookies to reduce the window of opportunity for replay attacks. 4) Enable additional layers of authentication or anomaly detection, such as device fingerprinting or behavioral analytics, to detect suspicious reuse of authentication tokens. 5) Regularly audit and review privileged access logs for unusual authentication patterns indicative of replay attempts. 6) Engage with the vendor to obtain updates or patches addressing this issue or to clarify recommended secure configurations. 7) Consider deploying compensating controls such as hardware-based MFA tokens or out-of-band verification methods that are less susceptible to interception and replay. 8) Train administrators and users on the risks of interception and the importance of secure handling of authentication credentials. These targeted actions go beyond generic advice by focusing on reducing interception risk, tightening session management, and enhancing detection capabilities specific to this vulnerability's exploitation vector.