CVE-2008-2726 in Ruby
Summary
by MITRE
Integer overflow in the (1) rb_ary_splice function in Ruby 1.8.4 and earlier, 1.8.5 before 1.8.5-p231, 1.8.6 before 1.8.6-p230, 1.8.7 before 1.8.7-p22, and 1.9.0 before 1.9.0-2; and (2) the rb_ary_replace function in 1.6.x allows context-dependent attackers to trigger memory corruption, aka the "beg + rlen" issue. NOTE: as of 20080624, there has been inconsistent usage of multiple CVE identifiers related to Ruby. The CVE description should be regarded as authoritative, although it is likely to change.
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Analysis
by VulDB Data Team • 08/12/2019
The vulnerability identified as CVE-2008-2726 represents a critical integer overflow flaw affecting multiple versions of the Ruby programming language, specifically targeting the rb_ary_splice and rb_ary_replace functions. This issue stems from improper handling of integer arithmetic during array manipulation operations, creating conditions where malicious input can cause unexpected behavior in memory management. The vulnerability affects Ruby versions 1.8.4 and earlier, 1.8.5 before 1.8.5-p231, 1.8.6 before 1.8.6-p230, 1.8.7 before 1.8.7-p22, and 1.9.0 before 1.9.0-2, making it a widespread concern across the Ruby ecosystem during that timeframe. The flaw is categorized under CWE-190 as an integer overflow condition, which occurs when an operation attempts to create a result that exceeds the maximum value that can be represented by the target data type.
The technical implementation of this vulnerability involves the manipulation of array indices and length parameters within the rb_ary_splice function, where the expression "beg + rlen" becomes problematic when integer overflow occurs. When attackers provide carefully crafted input parameters to these functions, the arithmetic operation can produce a value that wraps around to a small positive integer or even negative value due to integer overflow behavior. This creates a scenario where the application attempts to access memory locations that are either outside the allocated array bounds or at locations that could contain sensitive data, leading to potential memory corruption. The context-dependent nature of this vulnerability means that exploitation requires specific conditions and parameters that trigger the integer overflow condition, making it less straightforward to exploit but still highly dangerous when successful.
The operational impact of this vulnerability extends beyond simple memory corruption, potentially enabling attackers to execute arbitrary code or cause denial of service conditions within applications running vulnerable versions of Ruby. The memory corruption can manifest in various ways including segmentation faults, application crashes, or more insidiously, allow for code execution in the context of the running Ruby process. This vulnerability particularly affects web applications and scripts that handle user input through array manipulation operations, making it a significant concern for systems processing untrusted data. The issue is particularly dangerous in environments where Ruby is used for server-side scripting or web application development, as it could allow attackers to compromise entire application servers or gain unauthorized access to system resources.
Mitigation strategies for CVE-2008-2726 primarily involve upgrading to patched versions of Ruby, specifically versions 1.8.5-p231, 1.8.6-p230, 1.8.7-p22, and 1.9.0-2, which contain the necessary fixes for the integer overflow conditions. System administrators should prioritize patching affected Ruby installations and conducting thorough testing of applications to ensure compatibility with the updated versions. Additional defensive measures include implementing proper input validation and sanitization for array manipulation operations, particularly when processing user-supplied data that might be used as array indices or length parameters. The vulnerability demonstrates the importance of proper integer arithmetic handling in systems programming and aligns with ATT&CK technique T1059.007 for command and scripting interpreter, where attackers might exploit such vulnerabilities to execute malicious code within the Ruby environment. Organizations should also consider implementing runtime monitoring and anomaly detection to identify potential exploitation attempts targeting this vulnerability, as the integer overflow can create predictable patterns in memory access behavior that may be detectable through proper monitoring systems.