CVE-2009-0546 in FeedDemon
Summary
by MITRE
Stack-based buffer overflow in NewsGator FeedDemon 2.7 and earlier allows user-assisted remote attackers to execute arbitrary code via a long text attribute in an outline element in a .opml file.
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Analysis
by VulDB Data Team • 05/11/2025
The vulnerability identified as CVE-2009-0546 represents a critical stack-based buffer overflow flaw discovered in NewsGator FeedDemon version 2.7 and earlier. This vulnerability resides within the parsing mechanism of .opml files, which are commonly used for exporting and importing RSS feed subscriptions. The flaw specifically manifests when the application processes an outline element containing an excessively long text attribute, creating a condition where attacker-controlled data exceeds the bounds of a fixed-size stack buffer. This type of vulnerability falls under the CWE-121 category of Stack-based Buffer Overflow, where insufficient bounds checking allows memory corruption that can be exploited for arbitrary code execution. The vulnerability requires user interaction to be exploited, making it a user-assisted remote attack vector rather than a fully automated threat.
The technical exploitation of this vulnerability occurs through the manipulation of OPML file structures, specifically targeting the outline element's text attribute processing. When FeedDemon parses an OPML file containing a malformed outline element with an overly long text attribute, the application fails to validate the input length before copying it into a stack buffer. This insufficient input validation creates a predictable memory corruption scenario where the overflow can overwrite adjacent stack memory, potentially including return addresses and other critical control data. The attack requires an attacker to convince a victim to open a specially crafted malicious OPML file, making social engineering a necessary component of the exploitation process. This vulnerability directly maps to ATT&CK technique T1068 which covers 'Exploitation for Privilege Escalation' and T1203 which covers 'Exploitation for Client Execution'.
The operational impact of this vulnerability extends beyond simple code execution, as successful exploitation can lead to complete system compromise and privilege escalation. Attackers leveraging this vulnerability can gain arbitrary code execution with the privileges of the victim user, potentially enabling them to install malware, steal credentials, or establish persistent access to the compromised system. The vulnerability's presence in a widely used RSS feed reader application means that a successful attack could affect numerous users who regularly import subscription feeds from various sources. The user-assisted nature of the attack means that organizations must consider the broader threat landscape, including phishing campaigns and malicious content distribution through compromised websites or email attachments. The vulnerability represents a significant risk to enterprise environments where users may unknowingly import malicious feeds from untrusted sources, potentially leading to widespread compromise if multiple users are affected.
Mitigation strategies for CVE-2009-0546 should focus on immediate remediation through software updates and implementation of defensive measures. The primary and most effective mitigation is upgrading to FeedDemon version 2.8 or later, which includes proper bounds checking and input validation for OPML file parsing. Organizations should implement strict file validation policies for all OPML imports and consider disabling automatic feed import features for untrusted sources. Network-level defenses can include filtering of OPML file types at email gateways and web proxies, while endpoint protection solutions should be configured to monitor for suspicious file processing activities. Additionally, user education regarding the risks of opening OPML files from untrusted sources remains crucial, as the vulnerability requires user interaction to be exploited. Security monitoring should include detection of unusual file parsing patterns and memory corruption indicators that may signal exploitation attempts. The vulnerability serves as a reminder of the importance of input validation in all software components and the necessity of regular security updates to address known vulnerabilities in widely used applications.