attack-surface.md

Attack Surface Analysis for quick/nimble

Attack Surface: Malicious Package from Compromised Registry

• Description: Attackers compromise the Nimble package registry or mirrors and inject malicious packages or alter existing ones.
  • How Nimble Contributes: Nimble relies on package registries as its primary source for discovering and downloading packages. A compromised registry directly leads Nimble to fetch potentially malicious software.
  • Example: An attacker compromises the official Nimble registry and replaces the popular httpbeast package with a backdoored version. Developers using nimble install httpbeast will unknowingly install the malicious package from the legitimate Nimble tooling.
  • Impact: Full application compromise, data breaches, supply chain attack affecting all users of the malicious package, widespread distribution of malware through the Nimble ecosystem.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Use HTTPS for Registry Communication: Ensure Nimble and your system are configured to exclusively use HTTPS for all interactions with the package registry to protect against tampering in transit.
    • Package Signing and Verification (if available): Advocate for and utilize package signing and verification mechanisms within the Nimble ecosystem if they become available to ensure package integrity and authenticity.
    • Private/Mirrored Registries: For sensitive projects, consider using private or mirrored registries with stricter access control and security measures, bypassing the public registry entirely.
    • Regularly Audit Dependencies: Periodically review your project's dependencies and their sources, even from seemingly trusted registries, to detect any anomalies or unexpected changes.

Attack Surface: Man-in-the-Middle (MitM) Package Download

• Description: Attackers intercept package downloads during nimble install if insecure channels (like HTTP) are used, replacing legitimate packages with malicious ones during transit.
  • How Nimble Contributes: Nimble, if configured or allowed to download packages via insecure protocols (e.g., Git over HTTP, direct HTTP downloads), becomes vulnerable to MitM attacks during the download process.
  • Example: A developer on a compromised network attempts to install a package hosted on an HTTP Git repository using nimble install insecure-package. An attacker intercepts the HTTP traffic and replaces the legitimate Git repository with a malicious one. Nimble proceeds to clone and install the attacker's code.
  • Impact: Application compromise, potential system compromise if malicious installation scripts are included, introduction of backdoors or vulnerabilities into the application.
  • Risk Severity: High
  • Mitigation Strategies:
    • Enforce HTTPS for Package Sources: Configure Nimble and ensure package authors are using HTTPS for all package source URLs (Git, direct downloads) specified in nimble.toml and package definitions.
    • Verify Package Integrity (if possible): If checksums or signatures are provided by package authors or the registry, implement manual or automated verification steps after download and before installation to detect tampering.
    • Use Secure Networks: Perform package installations only on trusted and secure networks to minimize the risk of MitM attacks. Avoid public or untrusted Wi-Fi networks for development and dependency management tasks.
    • VPN Usage: Utilize a VPN when installing packages, especially on potentially untrusted networks, to encrypt network traffic and reduce MitM risks.

Attack Surface: Dependency Confusion/Substitution

• Description: Attackers register packages with names similar to internal or private dependencies in public registries, hoping Nimble will mistakenly prioritize and install the malicious public package.
  • How Nimble Contributes: Nimble's dependency resolution logic, if not carefully configured with explicit sources or priorities, might inadvertently resolve to and install packages from public registries when private or local packages with similar names are intended.
  • Example: A company uses an internal library named internal-auth-lib. An attacker registers a package with the same name, internal-auth-lib, on the public Nimble registry. If a developer within the company uses nimble install internal-auth-lib without specifying a private source, Nimble might install the attacker's malicious public package instead of the intended internal library.
  • Impact: Installation of attacker-controlled code intended for internal use, potentially granting unauthorized access to internal systems, data breaches, and compromise of internal applications.
  • Risk Severity: High
  • Mitigation Strategies:
    • Prioritize Private/Local Registries: Configure Nimble to prioritize private or local package repositories for internal dependencies by adjusting Nimble's configuration or using project-specific nimble.toml settings to define explicit package sources.
    • Explicit Dependency Sources: Clearly define and specify the source for each dependency in nimble.toml, especially for internal or private packages, to avoid ambiguity and ensure packages are fetched from the intended locations.
    • Package Namespacing: Use unique namespacing or prefixes for internal package names to significantly reduce the likelihood of naming collisions with packages in public registries.
    • Dependency Pinning and Verification: Pin specific versions of dependencies and implement verification mechanisms (if available) to ensure consistent and predictable installations from trusted sources.

Attack Surface: Malicious Installation Scripts (preInstall.nim, postInstall.nim)

• Description: Packages can include preInstall.nim and postInstall.nim scripts that Nimble executes during the installation process, allowing for arbitrary code execution.
  • How Nimble Contributes: Nimble's design includes the execution of these scripts as a standard part of the package installation workflow, inherently providing a mechanism for packages to run code on the user's system.
  • Example: A malicious package includes a postInstall.nim script that, upon execution by Nimble during installation (nimble install malicious-package), downloads and executes a backdoor, modifies system configuration files, or exfiltrates sensitive data. The script runs with the privileges of the user executing nimble install.
  • Impact: Arbitrary code execution on the developer's or user's system, system compromise, data exfiltration, privilege escalation, persistent backdoors.
  • Risk Severity: Critical
  • Mitigation Strategies:
    • Exercise Extreme Caution with Untrusted Packages: Be exceptionally cautious and avoid installing packages from unknown, unverified, or untrusted sources. Prioritize packages from reputable authors and well-established registries.
    • Review Installation Scripts Before Installation: If feasible and when dealing with less-trusted packages, manually review the contents of preInstall.nim and postInstall.nim scripts before proceeding with nimble install to identify any suspicious or malicious code.
    • Sandboxed Installation Environment: Consider running nimble install within a sandboxed environment (e.g., containers, virtual machines, or using operating system-level sandboxing features) to limit the potential impact of malicious installation scripts on the host system.
    • Package Scanning and Analysis Tools: Implement or utilize automated package scanning and analysis tools that can inspect packages and their installation scripts for potentially malicious code patterns or behaviors before installation.
    • Principle of Least Privilege for Installation: Run nimble install with the minimum necessary user privileges to reduce the potential damage from malicious scripts. Avoid running package installations as root or administrator unless absolutely necessary.

Attack Surface: Directory Traversal in Package Installation

• Description: Vulnerabilities in Nimble's package installation process or within package installation scripts could allow malicious packages to write files to arbitrary locations outside the intended package installation directory through directory traversal exploits.
  • How Nimble Contributes: Nimble's package extraction and installation logic, if not robustly implemented and secured, might be susceptible to directory traversal vulnerabilities when handling package archives or processing file paths within installation scripts.
  • Example: A malicious package is crafted with an archive containing filenames that include directory traversal sequences like "../" or "../../". When Nimble extracts this archive, a vulnerability in Nimble's archive handling or path processing allows files to be written to locations such as /etc/cron.d/ or ~/.bashrc instead of within the intended package directory.
  • Impact: Overwriting critical system files, privilege escalation by modifying system configurations, arbitrary code execution upon system reboot or user login if malicious files are placed in startup directories.
  • Risk Severity: High
  • Mitigation Strategies:
    • Keep Nimble Updated: Regularly update Nimble to the latest version to ensure you have the most recent security patches that address potential vulnerabilities, including directory traversal flaws in archive handling and installation processes.
    • Secure Archive Handling Libraries: Ensure Nimble utilizes secure and up-to-date archive extraction libraries that are specifically designed to prevent directory traversal vulnerabilities like zip-slip.
    • Input Sanitization and Validation: Implement rigorous input sanitization and validation within Nimble's code to properly handle and sanitize file paths extracted from package archives and processed during installation, preventing directory traversal sequences from being interpreted maliciously.
    • Principle of Least Privilege for Installation: Run Nimble installation processes with the minimum necessary privileges to limit the potential damage if a directory traversal vulnerability is exploited.
    • File System Integrity Monitoring: Implement file system integrity monitoring tools to detect unexpected or unauthorized file writes outside of expected package installation directories, which could indicate a directory traversal attack.

Attack Surface: Unsafe Handling of Package Archives (Zip-Slip)

• Description: Vulnerabilities like zip-slip in Nimble's archive extraction mechanisms allow malicious packages to write files outside the intended extraction directory, potentially overwriting system files or gaining unauthorized access.
  • How Nimble Contributes: Nimble's process of extracting package archives, if using vulnerable archive extraction libraries or lacking proper security checks, can be directly exploited by zip-slip vulnerabilities present in malicious package archives.
  • Example: A malicious package is crafted with a zip archive containing filenames like ../../../etc/malicious_file. When Nimble extracts this archive, a zip-slip vulnerability in Nimble's archive extraction library allows malicious_file to be written to /etc/ instead of within the package's intended directory.
  • Impact: System file overwrite, privilege escalation, arbitrary code execution, potential for persistent compromise if system startup files are modified.
  • Risk Severity: High
  • Mitigation Strategies:
    • Utilize Secure Archive Libraries: Ensure Nimble relies on secure and well-maintained archive extraction libraries that are known to be resistant to zip-slip and similar archive extraction vulnerabilities.
    • Path Sanitization and Validation: Implement robust path sanitization and validation within Nimble's archive extraction process to prevent filenames containing directory traversal sequences from being processed in a way that allows writing outside the intended directory.
    • Regular Nimble Updates: Keep Nimble updated to the latest version to benefit from security fixes and improvements in archive handling that address zip-slip and related vulnerabilities.
    • Archive Content Inspection (if feasible): If possible, implement mechanisms to inspect the contents of package archives before extraction to detect and reject archives containing suspicious filenames or directory traversal sequences.

Attack Surface: Vulnerabilities in Nimble Tooling

• Description: Nimble itself, as a software application, may contain vulnerabilities in its code (e.g., parsing logic, network communication, dependency resolution, archive handling) that can be exploited by attackers.
  • How Nimble Contributes: Nimble is the core tool responsible for package management. Vulnerabilities within Nimble directly expose users and applications to potential attacks through the package management process.
  • Example: A vulnerability in Nimble's TOML parsing library allows an attacker to craft a malicious nimble.toml file that, when processed by Nimble, triggers a buffer overflow or remote code execution within the Nimble process itself.
  • Impact: Arbitrary code execution within the Nimble process, bypassing security measures enforced by Nimble, potential compromise of the entire package management workflow, control over the Nimble installation process, and potentially broader system compromise if Nimble runs with elevated privileges.
  • Risk Severity: High to Critical (depending on the specific vulnerability)
  • Mitigation Strategies:
    • Keep Nimble Updated: Always use the latest stable version of Nimble. Regularly check for and apply updates to benefit from security patches and bug fixes released by the Nimble development team.
    • Monitor Security Advisories: Stay informed about security advisories and vulnerability reports related to Nimble. Subscribe to Nimble security mailing lists or monitor relevant security news sources to be promptly notified of any discovered vulnerabilities.
    • Report Vulnerabilities Responsibly: If you discover potential security vulnerabilities in Nimble, report them to the Nimble development team through their responsible disclosure channels to allow them to address and patch the issues.
    • Use Official Nimble Distributions: Download and install Nimble only from official and trusted sources (e.g., the official Nimble website, package repositories of your operating system) to avoid using tampered or backdoored versions of the Nimble tool itself.