CVE-2007-6628 in Feng
Summary
by MITRE
LScube Feng 0.1.15 and earlier allows remote attackers to cause a denial of service (NULL dereference and daemon crash) via (1) a malformed Transport header, which triggers misparsing in parse_transport_header in RTSP_setup.c, as demonstrated by a Transport header that contains only a "RTP/AVP;unicast;client_port" sequence; or (2) a malformed Range header, which triggers misparsing in parse_play_time_range in RTSP_Play, as demonstrated by an empty Range header.
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Analysis
by VulDB Data Team • 09/14/2018
The vulnerability identified as CVE-2007-6628 affects LScube Feng version 0.1.15 and earlier, representing a critical denial of service flaw in the RTSP (Real Time Streaming Protocol) implementation. This vulnerability stems from inadequate input validation and parsing mechanisms within the media streaming daemon, specifically targeting the RTSP_setup.c and RTSP_Play components. The flaw manifests when the system encounters malformed Transport and Range headers during RTSP session establishment and playback operations, leading to daemon crashes and complete service disruption.
The technical implementation of this vulnerability involves NULL pointer dereference conditions that occur during header parsing operations. When processing a Transport header containing only the sequence "RTP/AVP;unicast;client_port" without proper parameter validation, the parse_transport_header function in RTSP_setup.c fails to properly handle the minimal input, resulting in a NULL dereference error. Similarly, an empty Range header triggers a similar issue in the parse_play_time_range function within RTSP_Play, causing the daemon to crash due to improper boundary checking and memory access violations. These parsing failures represent classic CWE-476 Null Pointer Dereference conditions that fall under the broader category of input validation vulnerabilities.
The operational impact of this vulnerability extends beyond simple service disruption, as it provides remote attackers with a straightforward method to compromise the availability of streaming services. Attackers can exploit this weakness by sending specifically crafted RTSP requests containing malformed headers, causing the LScube Feng daemon to terminate unexpectedly and requiring manual intervention to restore service. This makes the vulnerability particularly dangerous in production environments where continuous streaming availability is critical, as it can be leveraged for denial of service attacks that may go unnoticed until service degradation occurs.
From a cybersecurity perspective, this vulnerability aligns with ATT&CK technique T1499.004 (Endpoint Denial of Service) and demonstrates poor defensive programming practices that violate secure coding guidelines. The flaw represents a failure to implement proper error handling and input sanitization, which are fundamental requirements in network service security. Organizations utilizing LScube Feng should immediately implement patches addressing the header parsing logic and consider implementing network-level protections such as rate limiting and header validation firewalls. Additionally, the vulnerability highlights the importance of robust input validation and proper error recovery mechanisms in streaming protocol implementations, as specified in industry standards such as RFC 2326 for RTSP protocol compliance and OWASP secure coding practices for preventing common web application vulnerabilities.
The remediation approach should focus on strengthening the parsing functions to handle malformed inputs gracefully, implementing proper NULL checks before pointer dereferences, and adding comprehensive input validation routines. Security teams should also consider deploying intrusion detection systems capable of identifying and blocking malformed RTSP headers, while maintaining detailed logging of suspicious network activity to detect potential exploitation attempts.