CVE-2015-3269 in Flex BlazeDS
Summary
by MITRE
Apache Flex BlazeDS, as used in flex-messaging-core.jar in Adobe LiveCycle Data Services (LCDS) 3.0.x before 3.0.0.354170, 4.5 before 4.5.1.354169, 4.6.2 before 4.6.2.354169, and 4.7 before 4.7.0.354169 and other products, allows remote attackers to read arbitrary files via an AMF message containing an XML external entity declaration in conjunction with an entity reference, related to an XML External Entity (XXE) issue.
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Analysis
by VulDB Data Team • 06/13/2022
Apache Flex BlazeDS represents a critical server-side messaging framework that facilitates communication between client applications and backend services through Action Message Format (AMF) protocol. The vulnerability CVE-2015-3269 specifically targets the XML parsing implementation within the flex-messaging-core.jar component, where the system fails to properly sanitize XML input received through AMF messages. This flaw enables attackers to construct malicious AMF payloads containing XML external entity declarations that reference local files on the server system. The vulnerability stems from the improper handling of XML entities during message processing, allowing an attacker to leverage XML External Entity processing to access arbitrary files on the target system. The issue affects multiple versions of Adobe LiveCycle Data Services and related products, making it a widespread concern across enterprise deployments that utilize these messaging frameworks.
The technical exploitation of this vulnerability follows a classic XML External Entity attack pattern where an attacker crafts an AMF message containing malicious XML with external entity declarations. When the vulnerable system processes this message, it attempts to resolve the external entity references, which can be configured to point to local files or network resources. The entity references can traverse directory structures and access sensitive files such as configuration files, database credentials, system files, or application data. This XXE vulnerability operates at the XML parser level, bypassing normal access controls and file system permissions that would normally prevent unauthorized file access. The attack can be executed remotely without requiring authentication or specific privileges on the target system, making it particularly dangerous for services that expose AMF endpoints to untrusted networks. The vulnerability is classified under CWE-611 as Improper Restriction of XML External Entity Reference, which directly maps to the core flaw in the XML processing logic.
The operational impact of CVE-2015-3269 extends beyond simple information disclosure, as successful exploitation can lead to complete system compromise and data exfiltration. Attackers can leverage this vulnerability to access sensitive configuration files containing database connection strings, encryption keys, and application credentials that are typically stored in local files. The vulnerability also enables attackers to perform reconnaissance activities by accessing system files and directory listings, potentially revealing system architecture details and application structure. In enterprise environments where LiveCycle Data Services is deployed, this vulnerability can provide attackers with access to business-critical data and internal system information. The remote nature of the attack means that even systems behind firewalls or network segmentation can be compromised if the AMF endpoints are accessible. This vulnerability aligns with ATT&CK technique T1059.007 for XML External Entity Processing and T1566 for Phishing, as attackers can use this weakness to gain initial access and establish persistence within target environments.
Organizations affected by this vulnerability should implement immediate mitigations including applying the vendor patches released for Adobe LiveCycle Data Services versions 3.0.0.354170, 4.5.1.354169, 4.6.2.354169, and 4.7.0.354169. The patch implementations typically involve updating the XML parsing libraries and implementing stricter input validation for AMF message processing. Network-level protections should include firewall rules that restrict access to AMF endpoints to trusted IP addresses only, and implementing web application firewalls that can detect and block malicious XML patterns in HTTP requests. Application-level mitigations include configuring XML parsers to disable external entity resolution and implementing input sanitization for all XML content received through AMF messages. Security monitoring should include log analysis for unusual file access patterns and XML parsing errors that may indicate exploitation attempts. The vulnerability also highlights the importance of regular security assessments and vulnerability scanning to identify similar XXE issues in other components of the application stack, particularly in systems that process untrusted XML input from network sources. Organizations should conduct thorough penetration testing to validate the effectiveness of implemented mitigations and ensure that no other XML parsing components within their infrastructure are similarly vulnerable to XXE attacks.