CVE-2017-7555 in Augeas
Summary
by MITRE
Augeas versions up to and including 1.8.0 are vulnerable to heap-based buffer overflow due to improper handling of escaped strings. Attacker could send crafted strings that would cause the application using augeas to copy past the end of a buffer, leading to a crash or possible code execution.
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Analysis
by VulDB Data Team • 12/16/2022
The vulnerability identified as CVE-2017-7555 represents a critical heap-based buffer overflow in Augeas library versions up to and including 1.8.0. This flaw resides in the library's handling of escaped strings during parsing operations, creating a scenario where malicious input can trigger memory corruption. The issue stems from inadequate bounds checking when processing string data that contains escape sequences, allowing attackers to manipulate memory layout through carefully crafted input patterns. Augeas is widely used for configuration file parsing and manipulation across various Linux distributions and network infrastructure tools, making this vulnerability particularly concerning for system administrators and security professionals.
The technical exploitation of this vulnerability occurs when Augeas processes configuration files or data structures containing malformed escape sequences. The buffer overflow manifests during string parsing operations where the library fails to properly validate the length of input strings before copying them into fixed-size memory buffers. This improper memory management creates opportunities for attackers to overwrite adjacent memory regions, potentially leading to application crashes or more severe consequences including arbitrary code execution. The vulnerability specifically affects the lens processing functionality within Augeas, which is responsible for parsing and transforming configuration data into structured formats for system management purposes.
From an operational perspective, the impact of CVE-2017-7555 extends beyond simple service disruption to potentially enable remote code execution on systems that utilize Augeas for configuration management. Since Augeas is integrated into numerous system tools, network management applications, and configuration automation frameworks, an attacker who can influence input to these systems may gain unauthorized access to underlying infrastructure. The vulnerability is particularly dangerous in environments where Augeas is used in conjunction with privilege escalation mechanisms or where it processes untrusted input from network sources. Systems running vulnerable versions may experience denial of service conditions or provide attackers with footholds for further compromise through the execution of malicious code within the application context.
Mitigation strategies for this vulnerability require immediate patching of Augeas to versions 1.8.1 or later where the buffer overflow has been addressed through proper bounds checking and input validation. System administrators should prioritize updating all affected systems and applications that depend on Augeas for configuration management. Additional defensive measures include implementing input validation at application layers that utilize Augeas, monitoring for unusual memory access patterns, and restricting network exposure to services that process untrusted configuration data. The vulnerability aligns with CWE-121 heap-based buffer overflow classification and represents a potential entry point for techniques described in the ATT&CK framework under privilege escalation and execution phases, particularly when combined with other exploitation vectors. Organizations should also consider implementing application whitelisting controls and network segmentation to limit potential attack surface exposure.