CVE-2018-5763 in eShop Enterprise Edition
Summary
by MITRE
An issue was discovered in OXID eShop Enterprise Edition before 5.3.7 and 6.x before 6.0.1. By entering specially crafted URLs, an attacker is able to bring the shop server to a standstill and hence, it stops working. This is only valid if OXID High Performance Option is activated and Varnish is used.
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Analysis
by VulDB Data Team • 01/07/2020
The vulnerability identified as CVE-2018-5763 represents a critical denial of service condition affecting OXID eShop Enterprise Edition systems. This weakness specifically targets installations utilizing the OXID High Performance Option alongside Varnish caching infrastructure, creating a scenario where malicious actors can exploit crafted URL patterns to cause complete service disruption. The vulnerability stems from insufficient input validation mechanisms within the URL processing framework of the eShop platform when operating in high-performance configurations. Attackers can construct specific URL sequences that, when processed by the system, trigger resource exhaustion or operational failures within the Varnish caching layer, ultimately leading to complete service unavailability.
The technical flaw manifests through improper handling of URL parameters and path structures within the OXID eShop's routing mechanisms when integrated with Varnish cache servers. This issue is categorized under CWE-400, representing an Uncontrolled Resource Consumption vulnerability, where the system fails to properly limit or validate input parameters that are subsequently processed by the caching infrastructure. The vulnerability operates at the application layer of the OSI model, specifically affecting the web application's ability to handle incoming requests efficiently. When malicious URLs are submitted, they can cause Varnish to consume excessive memory resources or enter infinite processing loops, effectively rendering the entire eShop platform inaccessible to legitimate users. The exploit requires the specific combination of OXID High Performance Option activation and Varnish implementation, making it a targeted vulnerability affecting only systems configured with these particular components.
The operational impact of this vulnerability extends beyond simple service disruption, creating potential financial and reputational damage for e-commerce operations relying on OXID eShop platforms. Organizations may experience complete loss of online sales capabilities, customer access interruptions, and potential data loss during the service outage periods. The vulnerability's exploitation can occur through automated scanning tools, making it particularly dangerous as attackers can systematically target multiple installations without requiring specialized knowledge or access privileges. From an attacker's perspective, this represents a low-effort, high-impact vector that can be executed using basic web browser capabilities or simple command-line tools. The vulnerability also creates opportunities for more sophisticated attacks, as initial service disruption can be used as a precursor to other exploitation techniques within the compromised environment.
Mitigation strategies for CVE-2018-5763 focus on both immediate patching and architectural considerations. Organizations should immediately upgrade their OXID eShop installations to versions 5.3.7 or 6.0.1, which contain the necessary code modifications to prevent the exploitation of crafted URLs. Additionally, implementing proper input validation at the web application firewall level can provide additional protection layers against malformed URL requests. Network-level restrictions should be considered to limit access to the vulnerable URL patterns, particularly when the Varnish caching infrastructure is exposed to untrusted networks. Security monitoring should be enhanced to detect unusual request patterns that may indicate exploitation attempts, and regular vulnerability assessments should be conducted to identify similar weaknesses in the broader application ecosystem. The ATT&CK framework categorizes this vulnerability under T1499.004, representing Network Denial of Service, highlighting the importance of implementing robust network security controls and maintaining up-to-date security patches across all system components to prevent such exploitation scenarios.