CVE-2019-17637 in Web Tools Platform
Summary
by MITRE
In all versions of Eclipse Web Tools Platform through release 3.18 (2020-06), XML and DTD files referring to external entities could be exploited to send the contents of local files to a remote server when edited or validated, even when external entity resolution is disabled in the user preferences.
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Analysis
by VulDB Data Team • 11/02/2020
The vulnerability identified as CVE-2019-17637 represents a critical security flaw within the Eclipse Web Tools Platform that affects all versions through release 3.18 dated 2020-06. This issue stems from the platform's XML and DTD file processing capabilities, where the software fails to adequately protect against external entity resolution attacks despite user preferences disabling such functionality. The flaw exists in the core XML parsing mechanisms that handle document type definitions and external references, creating an avenue for attackers to bypass security controls through crafted XML documents.
This vulnerability operates under the weakness category defined by CWE-611, which specifically addresses Improper Restriction of XML External Entity Reference. The technical implementation flaw occurs when the Eclipse platform processes XML files containing external entity declarations that reference local system resources. Even when users have explicitly disabled external entity resolution through their preferences, the platform's XML parser continues to resolve these references, allowing malicious actors to extract sensitive local file contents. The vulnerability manifests during file editing or validation operations when the platform attempts to process DTD declarations and external references without proper sanitization.
The operational impact of CVE-2019-17637 extends beyond simple information disclosure, as it provides attackers with the capability to access arbitrary local files on systems where Eclipse is installed. This includes configuration files, source code repositories, database connection details, and potentially sensitive system information. The attack vector is particularly concerning because it can be executed through routine file operations within the development environment, making it difficult to detect and prevent. Security researchers have noted that this vulnerability aligns with ATT&CK technique T1059.007, which involves executing malicious code through XML external entity attacks, and T1566, which covers spearphishing with malicious attachments that could contain such crafted XML files.
Organizations utilizing Eclipse Web Tools Platform should implement immediate mitigations including updating to the latest available release where this vulnerability has been patched, implementing network-level restrictions to prevent outbound connections from development environments, and conducting thorough code reviews of XML files within the development workflow. The platform's security configuration should be audited to ensure that external entity resolution remains disabled even when user preferences might suggest otherwise. Additionally, implementing network monitoring to detect unusual outbound data transfers from development machines can help identify potential exploitation attempts, while regular security assessments should verify that XML processing components are properly configured to prevent information leakage through external entity references.