CVE-2003-0882 in Mac OS X
Summary
by MITRE
Mac OS X before 10.3 initializes the TCP timestamp with a constant number, which allows remote attackers to determine the system s uptime via the ID field in a TCP packet.
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Analysis
by VulDB Data Team • 05/04/2019
The vulnerability described in CVE-2003-0882 represents a significant security flaw in Mac OS X versions prior to 10.3 where the operating system fails to properly randomize TCP timestamp values during network protocol initialization. This weakness stems from the system's initialization of TCP timestamps with a constant value rather than utilizing a cryptographically secure random number generator or system-specific entropy sources. The implementation violates fundamental principles of network security protocols and exposes systems to precise uptime determination by remote attackers who can analyze TCP packet headers.
The technical flaw manifests through the Transmission Control Protocol's timestamp option field, which is designed to provide accurate timing information for network communications and help prevent sequence number wraparound issues. When a system initializes TCP timestamps with a constant value, it creates predictable patterns that can be exploited by attackers monitoring network traffic. The ID field within TCP packets, when combined with the predictable timestamp values, allows adversaries to calculate the exact uptime of the target system with minimal network traffic analysis. This vulnerability directly relates to CWE-330 Use of Insufficiently Random Values and falls under the broader category of information disclosure vulnerabilities.
The operational impact of this vulnerability extends beyond simple uptime disclosure, as it provides attackers with crucial system information that can be leveraged in subsequent attacks. Knowing a system's uptime allows threat actors to better understand the system's state, potentially correlating this information with known vulnerabilities that affect specific time periods or system configurations. This information can be particularly valuable when combined with other reconnaissance techniques, enabling attackers to craft more targeted attacks or determine if a system has been recently rebooted, which might indicate a vulnerability window or system instability. The vulnerability affects the confidentiality aspect of the CIA triad and can be categorized under ATT&CK technique T1082 Discovery of System Information, specifically focusing on system uptime enumeration.
Mitigation strategies for this vulnerability require updating to Mac OS X 10.3 or later versions where the TCP timestamp initialization has been properly implemented with sufficient entropy. Network administrators should also implement proper network monitoring to detect unusual traffic patterns that might indicate active reconnaissance attempts targeting this specific vulnerability. Additionally, organizations should ensure that their network infrastructure properly handles TCP timestamp values and consider implementing network segmentation to limit the potential impact of such reconnaissance activities. The fix implemented by Apple addresses the root cause by ensuring that TCP timestamps are properly randomized during system initialization, thereby preventing attackers from deriving system uptime information through simple packet analysis.