CVE-2016-7511 in libdwarf
Summary
by MITRE
Integer overflow in the dwarf_die_deliv.c in libdwarf 20160613 allows remote attackers to cause a denial of service (crash) via a crafted file.
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Analysis
by VulDB Data Team • 08/15/2020
The vulnerability identified as CVE-2016-7511 represents a critical integer overflow flaw within the libdwarf library version 20160613 specifically within the dwarf_die_deliv.c component. This issue arises from improper handling of integer arithmetic operations when processing debug information files in the dwarf format. The flaw manifests when the library encounters malformed or crafted dwarf debug entries that trigger arithmetic overflow conditions during memory allocation calculations. Such overflow conditions can lead to unpredictable behavior including memory corruption, invalid memory access patterns, and ultimately system crashes. The vulnerability is particularly concerning because it affects a widely used library that provides debug information parsing capabilities for various software development and analysis tools.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious dwarf debug file containing specially constructed data that causes integer overflow during the processing of debug information entries. The dwarf_die_deliv.c module is responsible for delivering debug information entries to consumers of the libdwarf library, and it performs calculations to determine memory requirements for processing these entries. When integer overflow occurs in these calculations, the resulting invalid memory allocation sizes can cause the application to crash or behave unpredictably. This type of vulnerability falls under the CWE-190 category of integer overflow/underflow, which is classified as a fundamental flaw in arithmetic operation handling. The specific nature of the vulnerability aligns with ATT&CK technique T1499.004 for network denial of service attacks, where adversaries leverage software flaws to disrupt service availability.
The operational impact of CVE-2016-7511 extends beyond simple denial of service scenarios, as it can affect any system or application that relies on libdwarf for debug information processing. This includes software development environments, debugging tools, security analysis frameworks, and system monitoring applications that utilize dwarf format for symbol resolution and debugging purposes. The vulnerability is particularly dangerous in environments where automated processing of debug information occurs, such as continuous integration systems, security scanners, or applications that process user-uploaded files containing debug data. Attackers can exploit this vulnerability by delivering crafted dwarf files through various attack vectors including file uploads, network transfers, or malicious software packages. The crash condition typically results in immediate application termination, effectively causing a denial of service that can disrupt legitimate user operations and system availability. Systems that do not properly validate input data before passing it to libdwarf functions are particularly vulnerable to this attack vector.
Mitigation strategies for CVE-2016-7511 primarily focus on updating to patched versions of libdwarf that address the integer overflow conditions in dwarf_die_deliv.c. Organizations should prioritize updating their libdwarf installations to versions that include proper bounds checking and overflow protection mechanisms. Additionally, implementing input validation and sanitization measures can help reduce the attack surface by filtering out malformed dwarf debug entries before they reach the vulnerable code paths. Security measures should include monitoring for suspicious file uploads, implementing file type validation, and deploying intrusion detection systems that can identify attempts to exploit this vulnerability. The fix typically involves adding proper integer overflow checks in the memory allocation calculations within the dwarf_die_deliv.c module, ensuring that arithmetic operations are bounded and validated before proceeding with memory management operations. System administrators should also consider implementing application sandboxing or containerization to limit the potential impact of exploitation attempts, and regular security assessments should verify that all components utilizing libdwarf have been properly updated to prevent exploitation of this and similar vulnerabilities.