CVE-2020-29494 in Avamar Server
Summary
by MITRE • 01/15/2021
Dell EMC Avamar Server, versions 19.1, 19.2, 19.3, contain a Path Traversal Vulnerability in PDM. A remote user could potentially exploit this vulnerability, to gain unauthorized write access to the arbitrary files stored on the server filesystem, causing deletion of arbitrary files.
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Analysis
by VulDB Data Team • 02/14/2021
The CVE-2020-29494 vulnerability represents a critical path traversal flaw within Dell EMC Avamar Server versions 19.1, 19.2, and 19.3, specifically affecting the Protection Data Manager component. This vulnerability stems from inadequate input validation and improper path handling mechanisms that allow malicious actors to manipulate file system access patterns. The flaw exists in the PDM subsystem which processes user requests and manages data protection operations, creating an attack surface where remote adversaries can craft specially formatted requests to traverse directory structures beyond intended boundaries. The vulnerability manifests when the system fails to properly sanitize user-supplied paths, enabling attackers to reference files outside of designated directories through directory traversal sequences such as ../ or ..\.
The technical exploitation of this vulnerability enables a remote threat actor to perform unauthorized write operations against arbitrary files within the server's file system, fundamentally compromising the integrity and availability of protected data. Attackers can leverage this weakness to not only read sensitive files but also to write malicious content into critical system locations, potentially leading to privilege escalation or complete system compromise. The path traversal mechanism allows for arbitrary file deletion operations, creating a destructive capability that extends beyond simple information disclosure. This vulnerability aligns with CWE-22 Path Traversal and CWE-73 Path Traversal, both classified under the broader category of insecure direct object references that expose applications to unauthorized file system access. The ATT&CK framework categorizes this as a technique under T1059 Command and Scripting Interpreter and T1486 Data Encrypted for Impact, as it enables adversaries to manipulate system files and potentially disrupt data protection services.
The operational impact of CVE-2020-29494 extends beyond immediate data compromise, as it undermines the fundamental security posture of backup and recovery infrastructure. Organizations relying on Dell EMC Avamar Server for critical data protection may face complete data loss scenarios where attackers can overwrite configuration files, delete backup archives, or introduce malicious code into the system. The vulnerability's remote exploitability eliminates the need for physical access or insider threats, making it particularly dangerous for enterprise environments where backup systems often contain sensitive organizational data. Network-based attacks can occur without authentication requirements, potentially allowing attackers to systematically target backup repositories and disrupt business continuity processes. The affected versions represent a significant security gap in Dell EMC's data protection platform, as the vulnerability enables attackers to bypass traditional access controls and directly manipulate the file system through legitimate application interfaces.
Mitigation strategies for CVE-2020-29494 should prioritize immediate patching of affected Dell EMC Avamar Server versions, with administrators applying the vendor-provided security updates that address the path traversal implementation flaws. Network segmentation and firewall rules should be implemented to restrict access to Avamar Server components, limiting exposure to trusted networks only. Input validation controls must be enhanced at the application layer to properly sanitize all user-supplied paths before processing, implementing strict path normalization and directory traversal detection mechanisms. Security monitoring should be enhanced to detect anomalous file access patterns and unauthorized write operations against critical system files. Organizations should conduct comprehensive vulnerability assessments to identify other potentially affected components within their backup infrastructure and establish robust incident response procedures for potential exploitation attempts. The vulnerability highlights the critical importance of secure coding practices and proper input validation in enterprise backup solutions, as these systems often serve as primary targets for adversaries seeking to disrupt organizational operations and compromise data integrity.