CVE-2012-4562 in libssh
Summary
by MITRE
Multiple integer overflows in libssh before 0.5.3 allow remote attackers to cause a denial of service (infinite loop or crash) and possibly execute arbitrary code via unspecified vectors, which triggers a buffer overflow, infinite loop, or possibly some other unspecified vulnerabilities.
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Analysis
by VulDB Data Team • 12/20/2021
The vulnerability identified as CVE-2012-4562 represents a critical security flaw within the libssh library version 0.5.2 and earlier, affecting numerous systems that rely on secure shell communications. This issue stems from multiple integer overflow conditions that can be exploited by remote attackers to compromise system integrity and availability. The libssh library serves as a fundamental component for implementing ssh protocols in various applications and operating systems, making this vulnerability particularly concerning for widespread exploitation potential.
The technical implementation of this vulnerability manifests through integer overflows that occur during the processing of specific ssh protocol messages. When libssh encounters malformed data structures or oversized parameters in ssh communications, the integer variables used to manage buffer sizes and data lengths can exceed their maximum representable values. This overflow condition leads to unpredictable behavior where the library may attempt to allocate buffers of incorrect sizes or enter infinite loop conditions during processing. The flaw specifically affects the library's handling of packet sizes and data structures that are critical for maintaining secure communications between ssh clients and servers.
From an operational perspective, this vulnerability creates significant risks for affected systems as remote attackers can leverage these integer overflows to either crash the ssh service entirely or potentially execute arbitrary code on vulnerable systems. The denial of service aspect poses immediate operational concerns where legitimate users may be unable to establish secure connections, while the potential for arbitrary code execution represents a more severe threat that could allow attackers to gain unauthorized access to system resources. The unspecified vectors mentioned in the vulnerability description indicate that the flaw may be exploitable through multiple attack paths, increasing the overall risk surface for affected implementations.
The impact of CVE-2012-4562 aligns with common security frameworks such as CWE-190, which categorizes integer overflows as a fundamental weakness in software design that can lead to buffer overflows and other memory corruption issues. This vulnerability also maps to ATT&CK technique T1210, which describes exploitation of vulnerabilities in remote services to gain system access. Organizations using affected versions of libssh should consider this vulnerability as part of their broader security posture assessment, particularly in environments where ssh services are extensively utilized for administrative access and secure communications.
Mitigation strategies for this vulnerability primarily focus on immediate remediation through library updates to version 0.5.3 or later, which contain patches addressing the integer overflow conditions. System administrators should also implement network-level protections such as firewall rules that restrict ssh access to trusted sources and monitor for unusual ssh traffic patterns that might indicate exploitation attempts. Additionally, organizations should conduct comprehensive vulnerability assessments to identify all systems utilizing vulnerable libssh versions and establish monitoring procedures to detect potential exploitation attempts. The patching process should be prioritized based on the criticality of ssh services and the potential impact of compromise, with immediate attention given to systems handling sensitive data or serving as critical infrastructure components.