CVE-2017-17668 in S1 Dispenser Controller
Summary
by MITRE
Memory write mechanism in NCR S1 Dispenser controller before firmware version 0x0156 allows an unauthenticated user to upgrade or downgrade the firmware of the device, including to older versions with known vulnerabilities.
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Analysis
by VulDB Data Team • 01/15/2020
The vulnerability identified as CVE-2017-17668 resides within the NCR S1 Dispenser controller firmware ecosystem, specifically targeting devices operating with firmware versions prior to 0x0156. This security flaw represents a critical weakness in the device's firmware update mechanism that fundamentally compromises the integrity and security posture of the affected hardware. The vulnerability stems from inadequate authentication and authorization controls within the memory write process, creating an exploitable pathway for malicious actors to manipulate the device's firmware state without proper credentials or permissions.
The technical implementation of this vulnerability manifests through a flawed memory write mechanism that fails to properly validate the source or authenticity of firmware update requests. This weakness allows any unauthenticated user to initiate firmware upgrade or downgrade operations, effectively bypassing the normal security controls that should govern such critical system modifications. The flaw operates at the firmware level, where the controller's update protocol does not adequately verify the integrity or origin of firmware images, creating an attack surface that can be exploited by adversaries with network access to the device.
From an operational impact perspective, this vulnerability presents significant risks to organizations deploying NCR S1 Dispenser controllers in critical infrastructure environments. The ability to downgrade firmware to older versions with known vulnerabilities creates a persistent security risk where previously patched exploits can be re-introduced into the system. This capability enables attackers to potentially revert the device to a state with known security weaknesses, effectively nullifying any security improvements that may have been implemented in newer firmware versions. The impact extends beyond immediate security concerns to include potential operational disruptions and increased attack surface management complexity.
The vulnerability aligns with CWE-306, which addresses "Missing Authentication for Critical Function," as the firmware update mechanism lacks proper authentication requirements for critical system modification operations. Additionally, this weakness maps to ATT&CK technique T1072, "Software Deployment Tools," as it enables adversaries to manipulate legitimate deployment mechanisms for malicious firmware updates. Organizations utilizing these controllers face elevated risk of supply chain attacks and persistent threats that can exploit this vulnerability to establish long-term footholds within their infrastructure.
Effective mitigation strategies must include immediate firmware updates to version 0x0156 or later, which addresses the authentication bypass vulnerability in the firmware update mechanism. Network segmentation and access controls should be implemented to limit exposure of these devices to untrusted networks and users. Regular firmware inventory management and automated patch deployment processes should be established to ensure all devices maintain current security configurations. Device monitoring and anomaly detection systems should be deployed to identify unauthorized firmware modification attempts. Organizations should also conduct comprehensive security assessments of their dispenser controller deployments to identify and remediate similar vulnerabilities in other legacy systems. The vulnerability underscores the importance of maintaining up-to-date firmware and implementing robust security controls around critical infrastructure components that may not receive regular security attention.