CVE-2019-3752 in Avamar Server
Summary
by MITRE • 07/17/2021
Dell EMC Avamar Server versions 7.4.1, 7.5.0, 7.5.1, 18.2 and 19.1 and Dell EMC Integrated Data Protection Appliance (IDPA) versions 2.0, 2.1, 2.2, 2.3 and 2.4. contain an XML External Entity(XXE) Injection vulnerability. A remote unauthenticated malicious user could potentially exploit this vulnerability to cause Denial of Service or information exposure by supplying specially crafted document type definitions (DTDs) in an XML request.
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Analysis
by VulDB Data Team • 07/19/2021
The CVE-2019-3752 vulnerability represents a critical XML External Entity injection flaw discovered in Dell EMC Avamar Server and Integrated Data Protection Appliance products. This vulnerability stems from improper input validation within the XML processing components of these data protection systems, creating a pathway for remote attackers to manipulate the application's XML parser behavior. The affected versions span multiple release branches including Avamar Server 7.4.1, 7.5.0, 7.5.1, 18.2, and 19.1, alongside IDPA versions 2.0 through 2.4, indicating a widespread issue affecting Dell EMC's backup and recovery infrastructure solutions.
The technical exploitation of this XXE vulnerability occurs when malicious actors craft specially formatted XML requests containing malicious DTD definitions that trigger the XML parser to resolve external entities. This processing can lead to unauthorized data access, server resource exhaustion, or denial of service conditions. The vulnerability specifically targets the XML parsing mechanisms used by these systems for configuration management, data processing, and communication protocols. Attackers can leverage this flaw to access sensitive system information, potentially including credentials, configuration files, or other confidential data stored within the affected systems. The vulnerability is particularly concerning because it allows unauthenticated remote exploitation, meaning attackers do not require valid credentials to attempt the attack.
The operational impact of CVE-2019-3752 extends beyond simple denial of service conditions to potentially compromise the entire backup and recovery infrastructure. Organizations relying on Dell EMC Avamar and IDPA systems face significant risks including data exposure, system availability degradation, and potential escalation to broader network compromise. The vulnerability affects critical data protection services that organizations depend upon for business continuity and disaster recovery planning. Security teams must consider the implications of attackers potentially gaining access to backup data repositories, which could contain sensitive information across multiple systems and applications. This vulnerability directly relates to CWE-611, which describes improper restriction of XML external entity reference, and aligns with ATT&CK technique T1213.002 for data from information repositories, highlighting the potential for unauthorized data access through this vector.
Mitigation strategies for CVE-2019-3752 should prioritize immediate patch deployment from Dell EMC, as the vendor likely released security updates addressing the XML processing validation issues. Organizations should also implement network segmentation to limit access to these systems, disable unnecessary XML processing capabilities where possible, and establish monitoring for suspicious XML traffic patterns. Security configurations should enforce strict XML parser settings that disable external entity resolution and DTD processing. Additionally, organizations should conduct comprehensive vulnerability assessments to identify any other systems that might be exposed to similar XXE vulnerabilities, particularly those using similar XML processing frameworks. Regular security testing and input validation reviews should be implemented to prevent similar issues in future deployments. The vulnerability underscores the importance of secure coding practices and proper XML parser configuration in enterprise backup and recovery systems, particularly those handling sensitive organizational data.