CVE-2007-0538 in Server
Summary
by MITRE
Telligent Community Server 2.1 and earlier allows remote attackers to cause a denial of service (bandwidth or thread consumption) via pingback service calls with a source URI that corresponds to (1) a large file, which triggers a long download session without a timeout constraint; or (2) a file with a binary content type, which is downloaded even though it cannot contain usable pingback data.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 08/18/2018
The vulnerability described in CVE-2007-0538 represents a significant denial of service weakness in Telligent Community Server versions 2.1 and earlier. This flaw resides within the pingback service implementation, which is designed to notify web servers when links to their content are referenced elsewhere on the internet. The vulnerability exploits the server's handling of external URI references during pingback processing, creating a scenario where malicious actors can consume excessive system resources through carefully crafted service calls.
The technical implementation of this vulnerability stems from inadequate input validation and resource management within the pingback service component. When the server receives a pingback request containing a source URI, it attempts to download the referenced content to extract potential pingback data. However, the system lacks proper timeout mechanisms and content type validation, allowing attackers to specify URIs that lead to either large file downloads or binary content that cannot contain meaningful pingback information. This design flaw creates a resource exhaustion condition where the server's bandwidth and thread capacity become consumed by these malicious requests.
The operational impact of this vulnerability extends beyond simple service disruption, as it can lead to significant performance degradation and potential system instability. Attackers can maintain sustained resource consumption by repeatedly initiating pingback service calls with large files or binary content, effectively creating a bandwidth exhaustion attack. The lack of timeout constraints means that download sessions can persist indefinitely, consuming server threads and network resources. This type of attack directly violates the principle of resource isolation and can affect other legitimate users of the community platform.
From a cybersecurity perspective, this vulnerability aligns with CWE-400, which addresses "Uncontrolled Resource Consumption" and represents a classic example of a resource exhaustion attack. The flaw also demonstrates characteristics consistent with ATT&CK technique T1499.004, "Resource Hijacking," where adversaries consume system resources to impair availability of services. The vulnerability's exploitation requires minimal technical skill and can be automated, making it particularly dangerous in environments where community servers handle high volumes of traffic.
Mitigation strategies for this vulnerability should focus on implementing proper resource management controls within the pingback service. Organizations should establish explicit timeout constraints for all external content downloads, implement content type validation to reject binary files, and configure appropriate bandwidth limits for service requests. Additionally, rate limiting mechanisms should be deployed to prevent excessive pingback requests from single sources, while monitoring systems should be implemented to detect unusual resource consumption patterns. The most effective long-term solution involves upgrading to patched versions of Telligent Community Server where these resource management deficiencies have been addressed through proper input validation and timeout implementation.