CVE-2008-1391 in FreeBSD
Summary
by MITRE
Multiple integer overflows in libc in NetBSD 4.x, FreeBSD 6.x and 7.x, and probably other BSD and Apple Mac OS platforms allow context-dependent attackers to execute arbitrary code via large values of certain integer fields in the format argument to (1) the strfmon function in lib/libc/stdlib/strfmon.c, related to the GET_NUMBER macro; and (2) the printf function, related to left_prec and right_prec.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 11/28/2024
The vulnerability described in CVE-2008-1391 represents a critical integer overflow condition affecting multiple operating systems within the BSD family including NetBSD 4.x, FreeBSD 6.x and 7.x, and Apple Mac OS platforms. This issue stems from improper handling of integer values within the standard C library implementations, specifically impacting functions that process formatted output operations. The flaw manifests when attackers provide maliciously crafted large integer values in format arguments, creating conditions where integer arithmetic operations exceed their maximum representable values and wrap around to unexpected results. Such behavior creates exploitable conditions that can be leveraged to execute arbitrary code within the context of the affected application or system process.
The technical implementation of this vulnerability occurs within the libc library's handling of format strings, particularly affecting two distinct functions: the strfmon function located in lib/libc/stdlib/strfmon.c and the printf function. Both functions utilize macros and internal processing logic that fails to properly validate or constrain integer inputs, specifically related to the GET_NUMBER macro in strfmon and the left_prec and right_prec parameters in printf. When these functions process format strings containing excessively large integer values, the arithmetic operations involved in parsing these values can overflow the integer data types, leading to memory corruption that can be exploited by attackers. The vulnerability is context-dependent because it requires specific conditions to be met, including the ability to control input parameters to these formatting functions and the presence of executable code in memory locations that can be manipulated through the overflow conditions.
The operational impact of CVE-2008-1391 extends beyond simple system instability to potential complete system compromise. Attackers can leverage these integer overflows to manipulate memory layout, overwrite critical program data structures, or redirect execution flow to malicious code. The vulnerability affects fundamental system operations since strfmon and printf are widely used functions in both system utilities and application software, making the attack surface extensive. When exploited successfully, these vulnerabilities can allow attackers to execute arbitrary code with the privileges of the affected process, potentially leading to privilege escalation or complete system compromise. The integer overflow conditions create predictable memory corruption patterns that can be reliably exploited across multiple platforms due to the shared codebase architecture within the BSD family of operating systems, making this vulnerability particularly dangerous in environments where multiple affected systems coexist.
Mitigation strategies for CVE-2008-1391 require immediate system updates and patches from the respective operating system vendors, as the vulnerability affects core system libraries that are fundamental to proper system operation. System administrators should prioritize updating all affected platforms to patched versions of their operating systems, ensuring that the libc implementations contain proper integer validation and overflow protection mechanisms. Additionally, input validation should be implemented at application level to prevent untrusted data from reaching these vulnerable functions, particularly in applications that process user-provided format strings. Network segmentation and privilege separation can help limit the potential impact of successful exploitation, while monitoring systems should be configured to detect unusual patterns in system calls related to formatting functions. Organizations should also consider implementing address space layout randomization and stack canaries to make exploitation more difficult, though these are not complete solutions for integer overflow vulnerabilities. The vulnerability aligns with CWE-190, Integer Overflow or Wraparound, and represents a significant concern in the ATT&CK framework under the execution and privilege escalation tactics, particularly when considering the widespread use of affected system functions across various applications and system services.