CVE-2019-14295 in UPX
Summary
by MITRE
An Integer overflow in the getElfSections function in p_vmlinx.cpp in UPX 3.95 allows remote attackers to cause a denial of service (crash) via a skewed offset larger than the size of the PE section in a UPX packed executable, which triggers an allocation of excessive memory.
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Analysis
by VulDB Data Team • 04/11/2025
The vulnerability identified as CVE-2019-14295 represents a critical integer overflow flaw within the UPX packer software version 3.95. This issue resides in the getElfSections function located in the p_vmlinx.cpp source file, where improper handling of skewed offset values creates a condition that can be exploited remotely to trigger a denial of service attack. The flaw specifically manifests when processing PE sections within UPX packed executables, where an attacker can manipulate the offset values to exceed the legitimate size boundaries of the PE section structure. This manipulation causes the software to allocate excessive memory resources, ultimately leading to a crash of the packing process or the application attempting to execute the packed file.
The technical exploitation of this vulnerability follows a precise pattern where attackers craft malicious input files that contain manipulated PE section headers with inflated offset values. When UPX attempts to process these sections through the getElfSections function, the integer overflow occurs during the calculation of memory allocation requirements. The overflow results in the allocation of memory blocks that are orders of magnitude larger than what would be normally expected, causing the system to either consume all available memory resources or trigger a segmentation fault that terminates the process. This behavior aligns with CWE-190, which specifically addresses integer overflow conditions that can lead to memory allocation issues and subsequent system instability.
From an operational perspective, this vulnerability presents a significant risk to systems that rely on UPX for executable packing and distribution, particularly in enterprise environments where automated build processes or code signing workflows may inadvertently process maliciously crafted files. The remote attack vector means that adversaries can exploit this flaw without requiring local system access, making it particularly dangerous in web-based or networked environments where UPX packed executables are frequently encountered. The denial of service impact extends beyond simple application crashes, as the excessive memory allocation can cause system instability, resource exhaustion, and potentially affect other running processes on the same host system. This vulnerability directly maps to attack techniques described in the MITRE ATT&CK framework under the T1499 category for network denial of service, where adversaries seek to disrupt system availability through resource exhaustion.
The mitigation strategies for CVE-2019-14295 primarily involve immediate software updates to UPX versions that address the integer overflow condition in the getElfSections function. Organizations should implement strict input validation measures for any executable files processed through UPX, including signature verification and file integrity checks before packing operations. Additionally, system administrators should consider deploying network monitoring solutions that can detect unusual memory allocation patterns or excessive resource consumption that might indicate exploitation attempts. The vulnerability highlights the importance of proper integer handling and bounds checking in security-critical software components, emphasizing the need for comprehensive code review processes that specifically target mathematical operations and memory management functions. Organizations should also maintain awareness of similar vulnerabilities in other packer and unpacker tools, as integer overflows remain a common class of security flaws in binary processing software.