CVE-2018-2392 in Internet Graphics Server
Summary
by MITRE
Under certain conditions SAP Internet Graphics Server (IGS) 7.20, 7.20EXT, 7.45, 7.49, 7.53, fails to validate XML External Entity appropriately causing the SAP Internet Graphics Server (IGS) to become unavailable.
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Analysis
by VulDB Data Team • 01/05/2020
The vulnerability identified as CVE-2018-2392 affects SAP Internet Graphics Server versions 7.20, 7.20EXT, 7.45, 7.49, and 7.53, representing a critical weakness in XML processing that can lead to service disruption. This issue stems from inadequate validation of XML External Entity references within the IGS component, which is designed to handle graphic rendering and data processing for SAP applications. The vulnerability operates at the intersection of XML parsing security and denial of service conditions, creating a scenario where malicious actors can exploit malformed XML inputs to compromise system availability.
The technical flaw manifests when the SAP Internet Graphics Server processes XML documents containing external entity references without proper validation mechanisms. This weakness allows attackers to craft specially formatted XML requests that trigger the server to attempt to resolve external entities, potentially leading to resource exhaustion, network timeouts, or system crashes. The vulnerability aligns with CWE-611, which categorizes improper restriction of XML external entity reference as a significant security weakness. The improper handling of external entities creates a pathway for attackers to perform resource exhaustion attacks or cause the server to become unresponsive through excessive processing demands.
The operational impact of CVE-2018-2392 extends beyond simple service disruption to potentially compromise the entire SAP ecosystem's availability. When exploited successfully, the vulnerability can render the IGS component unavailable, which affects graphic rendering capabilities within SAP applications, potentially disrupting business processes that depend on visual data presentation. This vulnerability can be particularly damaging in enterprise environments where SAP systems handle critical business operations, as the unavailability of graphic services can cascade into broader operational disruptions. The attack vector typically involves sending malformed XML data to the IGS service, which then processes these inputs without proper validation, leading to system instability.
Mitigation strategies for this vulnerability should focus on implementing proper XML parsing controls and input validation mechanisms. Organizations should immediately apply SAP security patches and updates released to address this specific weakness, as these updates typically include enhanced XML entity validation routines. Network-level protections such as firewall rules that restrict access to the IGS service and implementation of XML filtering mechanisms can provide additional defense layers. The vulnerability also highlights the importance of following secure coding practices and adhering to the principle of least privilege for IGS services. From an ATT&CK framework perspective, this vulnerability maps to technique T1499.004, which covers network denial of service, and T1059.007, relating to scripting languages, as exploitation may involve crafting malicious XML payloads. Organizations should also implement monitoring solutions to detect unusual patterns in IGS service requests that could indicate exploitation attempts, while maintaining comprehensive logging of all XML processing activities for forensic analysis.