CVE-2017-17512 in sensible-utils
Summary
by MITRE
sensible-browser in sensible-utils before 0.0.11 does not validate strings before launching the program specified by the BROWSER environment variable, which allows remote attackers to conduct argument-injection attacks via a crafted URL, as demonstrated by a --proxy-pac-file argument.
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Analysis
by VulDB Data Team • 01/17/2023
The vulnerability identified as CVE-2017-17512 affects the sensible-browser component within the sensible-utils package, specifically versions prior to 0.0.11. This flaw represents a classic command injection vulnerability that arises from insufficient input validation mechanisms. The issue manifests when the application processes URLs through the BROWSER environment variable without proper sanitization of user-provided input, creating an avenue for malicious actors to manipulate the execution flow of the underlying browser launcher. The vulnerability is particularly concerning because it operates at the system integration level where user input directly influences program execution parameters.
The technical implementation of this vulnerability stems from the failure to validate or sanitize strings before incorporating them into command-line arguments for the browser executable. When a user provides a crafted URL containing malicious arguments, these inputs are directly passed to the BROWSER environment variable without proper parsing or escaping mechanisms. The demonstration of the vulnerability shows how attackers can inject arguments such as --proxy-pac-file, which can potentially redirect network traffic or execute unintended commands on the target system. This type of flaw falls under the CWE-77 schema, which categorizes improper neutralization of special elements used in OS commands, commonly known as OS command injection vulnerabilities.
From an operational perspective, this vulnerability enables remote attackers to conduct argument-injection attacks that can significantly compromise system security. The impact extends beyond simple browser manipulation to potentially allow attackers to redirect network traffic, intercept communications, or execute arbitrary code on the target system. The vulnerability is particularly dangerous in environments where users may encounter untrusted URLs or when the system is configured to automatically launch browsers for web content. The attack surface is broad since many applications rely on the sensible-browser utility for handling web browsing operations, making this vulnerability exploitable across multiple software components.
The security implications of CVE-2017-17512 align with the ATT&CK framework's command and control techniques, specifically targeting the execution of malicious commands through legitimate system utilities. This vulnerability can be leveraged in conjunction with other attack vectors to establish persistent access or escalate privileges within affected systems. The lack of input validation creates a direct pathway for attackers to manipulate the execution environment, potentially bypassing security controls that rely on proper command argument handling. Organizations using vulnerable versions of sensible-utils should immediately implement mitigation strategies including updating to patched versions, implementing proper input validation, and monitoring for suspicious browser launch patterns. The vulnerability demonstrates the critical importance of validating all user inputs before incorporating them into system commands, a principle that aligns with security best practices outlined in the OWASP Top Ten and similar industry standards for preventing injection attacks.