CVE-2017-16679 in SAP
Summary
by MITRE
URL redirection vulnerability in SAP's Startup Service, SAP KERNEL 32 NUC, SAP KERNEL 32 Unicode, SAP KERNEL 64 NUC, SAP KERNEL 64 Unicode 7.21, 7.21EXT, 7.22 and 7.22EXT; SAP KERNEL 7.21, 7.22, 7.45, 7.49 and 7.52, that allows an attacker to redirect users to a malicious site.
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Analysis
by VulDB Data Team • 12/13/2019
The CVE-2017-16679 vulnerability represents a critical URL redirection flaw within SAP's startup service components, specifically affecting multiple kernel versions including 32-bit and 64-bit NUC and Unicode variants across various SAP kernel releases. This vulnerability resides in the SAP KERNEL infrastructure and impacts the SAP Startup Service functionality, creating a significant security risk for organizations utilizing SAP systems. The flaw enables attackers to manipulate URL redirection mechanisms within the SAP environment, potentially compromising user sessions and leading to various downstream security incidents.
The technical implementation of this vulnerability stems from insufficient input validation and sanitization within the SAP KERNEL's URL handling mechanisms. Attackers can exploit this weakness by crafting malicious URLs that bypass normal validation checks, allowing unauthorized redirection to attacker-controlled domains. The vulnerability specifically affects the SAP KERNEL components that process and handle URL redirection requests during system startup and operation phases. This flaw operates at the application level and leverages the inherent trust relationships within SAP's internal systems, making it particularly dangerous as it can be exploited without requiring elevated privileges or complex attack vectors. The vulnerability aligns with CWE-601 URL Redirection to Untrusted Site ('Open Redirect') which is classified under the CWE top 25 most dangerous software weaknesses.
The operational impact of CVE-2017-16679 extends beyond simple phishing attacks, as it can enable more sophisticated attack chains within SAP environments. Security professionals should consider this vulnerability as part of the broader attack surface that could facilitate credential theft, session hijacking, and social engineering campaigns targeting SAP users. The vulnerability's presence in multiple kernel versions across different SAP releases creates widespread exposure across organizations, particularly those with legacy systems that may not have received timely updates. This flaw can be exploited to redirect users to malicious sites that appear legitimate within the SAP ecosystem, potentially bypassing security controls and user awareness training. The attack vector typically involves crafting specially formatted URLs that exploit the lack of proper validation in SAP's startup service components, making it particularly challenging to detect and prevent.
Organizations should implement immediate mitigations including applying SAP security notes and patches specifically addressing this vulnerability, as well as implementing network-level controls to monitor and restrict outbound URL redirection attempts. The recommended approach involves configuring SAP system parameters to enforce strict URL validation and implementing web application firewalls that can detect and block suspicious redirection patterns. Security teams should also conduct thorough vulnerability assessments to identify all affected SAP kernel versions and ensure comprehensive patch management processes are in place. Additionally, organizations should consider implementing user education programs to raise awareness about potential phishing attempts that may leverage this vulnerability, as well as establishing monitoring procedures that can detect anomalous URL redirection activities within SAP environments. The ATT&CK framework categorizes this vulnerability under T1566 Phishing and T1071.004 Application Layer Protocol: Web Protocols, emphasizing the need for both technical and user-focused defensive measures.