CVE-2021-27620 in Internet Graphics Service
Summary
by MITRE • 06/09/2021
SAP Internet Graphics Service, versions - 7.20,7.20EXT,7.53,7.20_EX2,7.81, allows an unauthenticated attacker after retrieving an existing system state value can submit a malicious IGS request over a network which due to insufficient input validation in method Ups::AddPart() which will trigger an internal memory corruption error in the system causing the system to crash and rendering it unavailable. In this attack, no data in the system can be viewed or modified.
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Analysis
by VulDB Data Team • 06/12/2021
SAP Internet Graphics Service represents a critical component within SAP systems that handles graphics processing and rendering for web-based applications. The vulnerability identified as CVE-2021-27620 affects multiple versions including 7.20, 7.20EXT, 7.53, 7.20_EX2, and 7.81, creating a widespread impact across various SAP deployments. This vulnerability specifically targets the Ups::AddPart() method within the IGS subsystem, where insufficient input validation creates a pathway for exploitation. The flaw manifests when an attacker can retrieve an existing system state value and subsequently submit a malicious IGS request over the network, exploiting the lack of proper validation mechanisms that should normally prevent malformed inputs from causing system instability.
The technical exploitation of this vulnerability involves a specific memory corruption error that occurs within the internal memory management of the SAP system. When the malicious request is processed through the vulnerable Ups::AddPart() method, the system's memory structures become corrupted, leading to an immediate system crash and complete service unavailability. This represents a denial of service condition that can be triggered by unauthenticated attackers who do not require any valid credentials or system access privileges to execute the attack. The vulnerability's classification aligns with CWE-121, which describes heap-based buffer overflow conditions, and specifically relates to insufficient input validation that allows attackers to manipulate system memory structures beyond their intended boundaries.
The operational impact of this vulnerability extends beyond simple service disruption as it affects the availability of critical business applications that depend on SAP Internet Graphics Service functionality. Organizations utilizing affected SAP versions face potential business interruption risks, particularly in environments where graphic rendering is essential for user interfaces, reporting systems, or web-based applications. The attack requires no data exfiltration or modification capabilities, making it purely a availability-focused threat that can be executed remotely without authentication. This characteristic places the vulnerability in the ATT&CK framework under the T1499.004 technique for network denial of service, where attackers can render systems unavailable through memory corruption attacks. The lack of data access capabilities means that while the system becomes unavailable, no sensitive information can be compromised through this specific vector, though the business impact remains significant due to operational disruption.
Mitigation strategies for CVE-2021-27620 should prioritize immediate patching of affected SAP systems through official SAP security notes and updates. Organizations must also implement network segmentation and access controls to limit exposure of SAP systems to untrusted networks, reducing the attack surface for potential exploitation attempts. Additional defensive measures include monitoring network traffic for suspicious IGS request patterns and implementing intrusion detection systems that can identify malformed requests targeting the vulnerable Ups::AddPart() method. Regular system health monitoring and automated alerting for service disruptions should be established to quickly identify exploitation attempts. Organizations should also conduct comprehensive vulnerability assessments to identify all systems running affected SAP Internet Graphics Service versions and prioritize remediation efforts based on business criticality and exposure levels. The vulnerability's nature makes it particularly suitable for automated exploitation, emphasizing the importance of proactive security measures and regular patch management processes to prevent successful exploitation attempts.