CVE-2008-2725 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, and 1.8.7 before 1.8.7-p22; and (2) the rb_ary_replace function in 1.6.x allows context-dependent attackers to trigger memory corruption via unspecified vectors, aka the "REALLOC_N" variant, a different issue than CVE-2008-2662, CVE-2008-2663, and CVE-2008-2664. 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 described in CVE-2008-2725 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 vulnerability falls under the CWE-190 category of Integer Overflow or Wraparound, which occurs when an integer operation produces a result that exceeds the maximum value that can be represented by the integer type. The flaw 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 1.6.x series, making it a widespread issue across the Ruby ecosystem during that time period.
The technical implementation of this vulnerability stems from improper handling of integer values within the memory allocation routines of Ruby's array manipulation functions. When the rb_ary_splice and rb_ary_replace functions process array operations, they fail to properly validate integer inputs that control memory allocation sizes. This allows attackers to craft malicious inputs that cause integer overflow conditions, resulting in incorrect memory calculations that can lead to memory corruption. The vulnerability specifically affects the REALLOC_N mechanism, which is responsible for reallocation of memory blocks in Ruby's array implementation. The flaw operates through context-dependent attack vectors where the attacker must control specific array parameters that influence the calculation of memory allocation sizes.
From an operational perspective, this vulnerability presents a significant security risk as it can be exploited to trigger memory corruption that may lead to arbitrary code execution. Attackers can leverage this flaw by providing carefully crafted array parameters that, when processed by the vulnerable functions, cause the integer overflow to result in unexpected memory layout changes. The memory corruption can manifest in various ways including buffer overflows, use-after-free conditions, or other memory-related vulnerabilities that could be exploited to gain unauthorized access to systems running vulnerable Ruby applications. This makes the vulnerability particularly dangerous in web applications or any environment where Ruby processes untrusted input data through array manipulation functions.
The impact of this vulnerability extends beyond simple memory corruption, as it can be leveraged to bypass security mechanisms and potentially escalate privileges within affected systems. The ATT&CK framework categorizes this type of vulnerability under the T1190 technique of Exploit Public-Facing Application, as it represents a flaw in a widely used application framework that could be exploited through web applications. Organizations running Ruby applications are particularly vulnerable since the flaw affects multiple versions of the language, requiring comprehensive patch management across all affected systems. The vulnerability's classification as a memory corruption issue also aligns with the CWE-121 category of Stack-based Buffer Overflow, though it manifests differently through integer overflow conditions.
Mitigation strategies for CVE-2008-2725 primarily involve immediate patching of affected Ruby installations to versions that contain the necessary fixes for integer overflow protection. System administrators should prioritize updating Ruby to versions 1.8.5-p231, 1.8.6-p230, or 1.8.7-p22 and later, as these releases contain the appropriate safeguards against integer overflow conditions in the rb_ary_splice and rb_ary_replace functions. Additionally, input validation should be implemented at application level to prevent potentially malicious array parameters from reaching the vulnerable functions. The implementation of address space layout randomization and stack canaries can provide additional defense-in-depth measures. Organizations should also conduct thorough vulnerability assessments to identify any custom Ruby applications that may be affected by this issue, as third-party libraries or application code that utilizes these functions could also be vulnerable. Regular security monitoring and maintaining updated vulnerability databases are essential for preventing exploitation of this and similar memory corruption vulnerabilities in the Ruby runtime environment.