Apache Xerces-C XML Parser Nested DTD Denial of Service Vulnerability [CVE-2016-4463]
CVE Number – CVE-2016-4463
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A vulnerability in the Apache Xerces-C XML parser could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on a targeted system.
The vulnerability is due to improper parsing of deeply nested Document Type Definition (DTD) markup declarations by the affected software. An attacker could exploit this vulnerability by persuading a user to execute an application that uses the affected software to access an XML file that submits malicious DTDs to a targeted system. A successful exploit could cause a stack overflow condition that causes the application to crash, resulting in a DoS condition.
Apache has confirmed the vulnerability and released software updates.
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To exploit this vulnerability, an attacker may persuade a user to access an XML file that submits malicious input to the targeted system by using misleading language and instructions.
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Administrators are advised to apply the appropriate updates.
Administrators are advised to allow only trusted users to have network access.
Users are advised not to open email messages from suspicious or unrecognized sources. If users cannot verify that links or attachments included in email messages are safe, they are advised not to open them.
Users are advised not to visit websites or follow links that have suspicious characteristics or cannot be verified as safe.
Administrators are advised to use an unprivileged account when browsing the Internet.
Administrators are advised to monitor critical systems.
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Apache has released a security advisory at the following link: CVE-2016-4463: Apache Xerces-C XML Parser Crashes on Malformed DTD
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Apache has released software updates at the following link: Xerces-C 3.1.4 or later
Duncan is a technology professional with over 20 years experience of working in various IT roles. He has a interest in cyber security, and has a wide range of other skills in radio, electronics and telecommunications.