CVE-2015-5571 in Flash Player
Summary
by MITRE
Adobe Flash Player before 18.0.0.241 and 19.x before 19.0.0.185 on Windows and OS X and before 11.2.202.521 on Linux, Adobe AIR before 19.0.0.190, Adobe AIR SDK before 19.0.0.190, and Adobe AIR SDK & Compiler before 19.0.0.190 do not properly restrict the SWF file format, which allows remote attackers to conduct cross-site request forgery (CSRF) attacks against JSONP endpoints, and obtain sensitive information, via a crafted OBJECT element with SWF content satisfying the character-set requirements of a callback API. NOTE: this issue exists because of an incomplete fix for CVE-2014-4671 and CVE-2014-5333.
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Analysis
by VulDB Data Team • 06/18/2022
Adobe Flash Player versions prior to 18.0.0.241 on Windows and OS X, and before 11.2.202.521 on Linux, along with Adobe AIR versions before 19.0.0.190 and corresponding SDK versions, contained a critical vulnerability that stemmed from inadequate restrictions on the SWF file format. This flaw represented a regression in security controls that had previously been addressed in CVE-2014-4671 and CVE-2014-5333, demonstrating the persistent challenges in implementing robust content validation mechanisms within multimedia frameworks. The vulnerability specifically exploited the manner in which Flash Player handled OBJECT elements containing SWF content, particularly when these elements satisfied certain character-set requirements of callback APIs that were designed to interface with JSONP endpoints. The technical implementation allowed malicious actors to craft specially formatted OBJECT elements that could trigger unintended cross-site request forgery attacks against web applications that relied on JSONP for data retrieval operations. This particular flaw manifested through the improper validation of SWF file content, enabling attackers to bypass security controls that were intended to prevent unauthorized access to sensitive information through JSONP endpoints.
The operational impact of this vulnerability extended beyond simple data exfiltration, as it enabled attackers to perform authenticated operations against web applications that utilized JSONP for cross-domain communication. The flaw particularly affected applications that implemented callback-based APIs where the response format was expected to be processed as JavaScript code, creating a vector for attackers to manipulate these endpoints and potentially gain access to user sessions, personal data, or other sensitive information. The vulnerability's persistence across multiple platforms and versions of Adobe's multimedia framework highlighted the complexity of maintaining secure content handling across diverse operating environments, particularly when dealing with legacy systems that required backward compatibility. Security researchers identified that the incomplete fix for previous vulnerabilities had left gaps in the validation process, specifically concerning the character-set requirements that were necessary for proper callback API handling. This oversight allowed attackers to exploit the SWF content parsing mechanism in a manner that could be used to construct malicious requests that would be processed by the target application's JSONP endpoints without proper authentication checks.
The exploitation of this vulnerability required attackers to craft specific OBJECT elements containing SWF content that would satisfy the character-set requirements of targeted callback APIs, effectively enabling a form of automated cross-site request forgery. The attack vector demonstrated how multimedia frameworks could inadvertently become attack surfaces for information disclosure and unauthorized access, particularly when they failed to properly validate content that would be processed in sensitive contexts. Organizations using affected versions of Adobe Flash Player and AIR were particularly vulnerable because these frameworks were commonly deployed across enterprise environments and consumer applications, creating widespread potential for exploitation. The vulnerability's classification aligns with CWE-798, which addresses the use of hard-coded credentials and improper input validation, as well as CWE-346, concerning the lack of proper validation of source of data. From an ATT&CK framework perspective, this vulnerability mapped to T1190, which describes the use of valid accounts for unauthorized access, and T1071, addressing application layer protocols that could be leveraged for data exfiltration. The remediation required updating to patched versions of Adobe Flash Player and AIR, which implemented proper restrictions on SWF file format handling and improved validation of content that would be processed through JSONP endpoints. Security teams needed to prioritize this vulnerability due to its potential for widespread impact across multiple platforms and the relatively simple nature of the exploitation technique, which did not require sophisticated attack infrastructure or deep technical knowledge to implement successfully.