CVE-2020-35457 in GLib
Summary
by MITRE • 12/15/2020
** DISPUTED ** GNOME GLib before 2.65.3 has an integer overflow, that might lead to an out-of-bounds write, in g_option_group_add_entries. NOTE: the vendor's position is "Realistically this is not a security issue. The standard pattern is for callers to provide a static list of option entries in a fixed number of calls to g_option_group_add_entries()." The researcher states that this pattern is undocumented.
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Analysis
by VulDB Data Team • 08/04/2024
The vulnerability identified as CVE-2020-35457 affects GNOME GLib library versions prior to 2.65.3, specifically within the g_option_group_add_entries function. This integer overflow represents a potential security concern that could result in out-of-bounds write conditions. The issue stems from insufficient input validation and boundary checking when processing option entries within the GLib option parsing framework. The vulnerability is classified under CWE-190 as an integer overflow condition, where an integer value exceeds its maximum representable value and wraps around to a smaller value, potentially causing memory corruption.
The technical flaw manifests when the g_option_group_add_entries function processes a large number of option entries that could cause integer overflow during internal calculations. This overflow condition can occur when the number of entries exceeds the maximum value that can be represented by the integer type used for counting, leading to incorrect memory allocation calculations. The out-of-bounds write vulnerability arises when the system attempts to write data beyond the allocated memory boundaries, potentially allowing malicious actors to corrupt memory or execute arbitrary code.
From an operational perspective, the impact of this vulnerability depends heavily on how the GLib library is utilized within applications. The vendor's position that this is not a security issue stems from their assertion that typical usage patterns involve static lists of option entries provided in fixed numbers of calls to g_option_group_add_entries. However, this pattern is not officially documented, creating a gap between vendor expectations and actual implementation practices. The vulnerability becomes more concerning when applications dynamically generate option entries or when input validation is insufficient, potentially allowing attackers to manipulate the number of entries to trigger the overflow condition.
The security implications extend beyond simple memory corruption, as this vulnerability could enable privilege escalation or denial of service attacks in applications that rely heavily on GLib's option parsing functionality. Attackers could potentially exploit this by crafting malicious input that causes the integer overflow, leading to memory corruption that might be leveraged for code execution or system instability. The vulnerability affects applications across multiple platforms that use GNOME GLib for command-line option parsing, including desktop applications, system utilities, and server applications.
Mitigation strategies should focus on upgrading to GLib version 2.65.3 or later, where the integer overflow has been addressed through proper boundary checking and input validation. Organizations should also implement code reviews to ensure that applications properly validate the number and size of option entries before processing them through g_option_group_add_entries. Additionally, input sanitization measures should be implemented to prevent maliciously crafted option entry counts from reaching the vulnerable function. The ATT&CK framework categorizes this vulnerability under T1059.007 for command and scripting interpreter, as exploitation might involve manipulating command-line arguments, and potentially T1068 for exploit for privilege escalation if the vulnerability leads to code execution.
The disputed nature of this vulnerability highlights the importance of vendor communication and documentation standards in security assessments. While the vendor considers this not a security issue due to their interpretation of usage patterns, the researcher's position that the documented pattern is undocumented creates uncertainty about the true risk profile. This discrepancy underscores the need for comprehensive testing and validation of security assumptions, particularly when vendor positions may not align with actual usage patterns in the field. Organizations should implement defensive measures regardless of vendor positions, as the potential for exploitation exists when applications do not strictly follow the documented usage patterns, making this vulnerability a legitimate concern for security-conscious deployments.