CVE-2005-0191 in RealPlayer
Summary
by MITRE
Off-by-one buffer overflow in the processing of tags in Real Metadata Package (RMP) files in RealPlayer 10.5 (6.0.12.1040) and earlier could allow remote attackers to execute arbitrary code via a long tag.
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Analysis
by VulDB Data Team • 06/12/2019
The vulnerability described in CVE-2005-0191 represents a critical buffer overflow condition that existed within RealPlayer's handling of Real Metadata Package files. This flaw specifically manifested in the processing of tags within RMP files, where the software failed to properly validate the length of incoming data before copying it into fixed-size buffers. The issue stemmed from an off-by-one error in the boundary checking logic, which allowed an attacker to exceed the intended buffer limits by a single byte. This type of vulnerability falls under the CWE-121 category of buffer overflow conditions, specifically representing a classic stack-based buffer overflow scenario that has been a persistent threat in software development for decades. The vulnerability was present in RealPlayer versions 10.5 and earlier, with the specific build identifier 6.0.12.1040, indicating this was part of a broader class of memory corruption flaws that plagued multimedia applications during this period.
The operational impact of this vulnerability was severe and directly exploitable by remote attackers. When a victim opened a maliciously crafted RMP file, the buffer overflow would occur during tag processing, potentially allowing an attacker to overwrite adjacent memory locations including return addresses and control data. This memory corruption could be leveraged to execute arbitrary code with the privileges of the user running RealPlayer, effectively providing a complete system compromise. The attack vector required only that a user open a specially crafted RMP file, making it particularly dangerous as it could be delivered through email attachments, web downloads, or file sharing networks. The vulnerability's exploitation aligns with the ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation would enable attackers to execute malicious payloads on victim systems. The flaw's nature made it particularly attractive to threat actors as it could be easily automated and did not require any special user interaction beyond normal file opening behavior, creating a significant risk for widespread exploitation.
The technical implementation of this vulnerability demonstrates how seemingly simple parsing logic can create catastrophic security implications. RealPlayer's RMP file parser did not properly validate tag lengths against buffer boundaries, allowing an attacker to craft a tag that was one byte longer than the allocated buffer space. This single-byte overflow could overwrite critical memory structures, potentially enabling stack smashing or return address corruption. The vulnerability's exploitation required careful crafting of the malicious RMP file to ensure the overflow would redirect execution flow to attacker-controlled code. Security researchers identified this as a classic example of unsafe string handling practices that were common in multimedia applications of that era. The flaw's presence in RealPlayer's codebase highlights the importance of input validation and proper boundary checking in all software components, particularly those handling user-supplied data. Organizations should have implemented immediate mitigations including disabling RMP file support, updating to patched versions, and implementing network-based controls to prevent access to potentially malicious RMP files. The vulnerability serves as a historical example of how buffer overflows continue to represent one of the most prevalent and dangerous classes of software vulnerabilities, warranting continued attention in modern security practices and emphasizing the need for robust input validation and memory safety mechanisms in all software development processes.