CVE-2018-6913 in Perl
Summary
by MITRE
Heap-based buffer overflow in the pack function in Perl before 5.26.2 allows context-dependent attackers to execute arbitrary code via a large item count.
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Analysis
by VulDB Data Team • 02/28/2023
The heap-based buffer overflow vulnerability identified as CVE-2018-6913 affects Perl versions prior to 5.26.2 and resides within the pack function implementation. This vulnerability represents a critical security flaw that can be exploited by context-dependent attackers to execute arbitrary code on affected systems. The flaw specifically manifests when the pack function processes a large item count, leading to improper memory management and subsequent heap corruption. The vulnerability falls under the Common Weakness Enumeration category CWE-122, which describes weakness in which a program allocates a buffer but fails to properly check the size of the data being copied into the buffer, resulting in heap overflow conditions. The pack function in Perl is designed to convert data into a binary format, but the implementation contains a flaw where it does not adequately validate the item count parameter, allowing attackers to manipulate this value to trigger memory corruption. This type of vulnerability is particularly dangerous because it can be leveraged to achieve remote code execution, making it a significant concern for systems that process untrusted data through Perl applications. The attack vector requires an attacker to have the ability to influence the item count parameter passed to the pack function, which may be possible in scenarios where Perl applications handle user input or external data sources without proper validation. The operational impact of this vulnerability extends beyond simple code execution, as successful exploitation can lead to complete system compromise, data theft, and denial of service conditions. Attackers can potentially leverage this vulnerability to gain elevated privileges, install backdoors, or establish persistent access to affected systems. The vulnerability's exploitation requires a specific context where the attacker can control the input parameters to the pack function, making it somewhat more difficult to exploit than direct buffer overflow vulnerabilities but still poses a substantial risk to affected environments. Organizations running Perl applications that process external data or user input are particularly vulnerable to this attack vector. The remediation strategy involves upgrading to Perl version 5.26.2 or later, which includes patches addressing the heap buffer overflow in the pack function implementation. System administrators should also implement input validation measures to prevent malicious data from reaching vulnerable functions, though the primary mitigation remains the software update. The vulnerability demonstrates the importance of proper memory management in interpreted languages and highlights the need for comprehensive security testing of core library functions. From an enterprise security perspective, this vulnerability aligns with ATT&CK technique T1059.007 for the use of scripting languages, as it affects Perl scripting environments and can be exploited through malicious script execution. Organizations should also consider implementing network segmentation and monitoring to detect potential exploitation attempts, as the vulnerability may be used in broader attack campaigns targeting web applications and automated systems that rely on Perl for processing. The flaw underscores the critical importance of keeping interpreted language environments updated, as these vulnerabilities can remain undetected for extended periods and can be leveraged in sophisticated attack chains that may include multiple exploitation techniques.