CVE-2017-1000231 in ldns
Summary
by MITRE
A double-free vulnerability in parse.c in ldns 1.7.0 have unspecified impact and attack vectors.
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Analysis
by VulDB Data Team • 01/10/2023
The double-free vulnerability identified in CVE-2017-1000231 resides within the ldns 1.7.0 library's parse.c component, representing a critical memory management flaw that can lead to arbitrary code execution under specific conditions. This vulnerability manifests when the library processes malformed DNS responses or records, causing the application to free the same memory block twice during the parsing operation. The flaw occurs in the context of DNS resolution and parsing functionality, making it particularly dangerous for network services that rely on ldns for DNS protocol handling.
The technical implementation of this vulnerability stems from improper memory deallocation logic within the DNS record parsing functions. When ldns encounters certain malformed input data structures, the parsing routine executes a sequence where a memory pointer is freed and subsequently freed again without proper validation. This double-free condition creates a memory corruption state that can be exploited by malicious actors to manipulate heap memory layout. The vulnerability specifically affects the ldns library's ability to handle certain DNS resource record formats, particularly those involving complex nested structures or malformed data that triggers the problematic parsing path.
From an operational standpoint, this vulnerability presents significant risks to systems utilizing ldns for DNS resolution and network protocol analysis. Network infrastructure services such as DNS servers, caching servers, and security monitoring tools that depend on ldns for DNS processing are particularly vulnerable. The unspecified impact and attack vectors indicate that exploitation could potentially lead to complete system compromise, denial of service conditions, or information disclosure. The vulnerability's exploitation requires careful crafting of malicious DNS responses or records that trigger the specific parsing path, making it moderately difficult to exploit but highly impactful when successful.
The vulnerability aligns with CWE-415, which describes double free conditions in memory management, and can be mapped to ATT&CK technique T1059 for command execution through compromised network services. Organizations using ldns in production environments face potential exposure through DNS-based attacks, where attackers could craft malicious DNS responses to exploit this vulnerability in systems processing DNS traffic. The impact extends beyond simple service disruption to include potential privilege escalation and persistent access to compromised systems. Security teams should prioritize patching affected systems and implementing network monitoring to detect potential exploitation attempts through malformed DNS traffic patterns.
Mitigation strategies should include immediate patching of ldns to versions containing the fix for this double-free vulnerability, along with implementing network segmentation to limit exposure of vulnerable services. Additional protective measures involve deploying DNS traffic filtering rules that can detect and block malformed DNS responses, as well as monitoring for unusual DNS processing patterns that might indicate exploitation attempts. Organizations should also consider implementing memory protection mechanisms such as stack canaries and address space layout randomization to reduce the effectiveness of potential exploitation attempts. Regular vulnerability assessments should be conducted to identify other potential memory corruption issues within the DNS processing stack and ensure comprehensive protection against similar vulnerabilities.