CAPEC 126 Path Traversal

Draft Standard High Risk

Severity Very High

Description

An adversary uses path manipulation methods to exploit insufficient input validation of a target to obtain access to data that should be not be retrievable by ordinary well-formed requests. A typical variety of this attack involves specifying a path to a desired file together with dot-dot-slash characters, resulting in the file access API or function traversing out of the intended directory structure and into the root file system. By replacing or modifying the expected path information the access function or API retrieves the file desired by the attacker. These attacks either involve the attacker providing a complete path to a targeted file or using control characters (e.g. path separators (/ or \\) and/or dots (.)) to reach desired directories or files.

Attack Execution Flow

Step 1

Explore

[Fingerprinting of the operating system] In order to perform a valid path traversal, the attacker needs to know what the underlying OS is so that the proper file seperator is used.
Port mapping. Identify ports that the system is listening on, and attempt to identify inputs and protocol types on those ports.
TCP/IP Fingerprinting. The attacker uses various software to make connections or partial connections and observe idiosyncratic responses from the operating system. Using those responses, they attempt to guess the actual operating system.
Induce errors to find informative error messages

Attack Techniques

TCP/IP Fingerprinting. The attacker uses various software to make connections or partial connections and observe idiosyncratic responses from the operating system. Using those responses, they attempt to guess the actual operating system.
Port mapping. Identify ports that the system is listening on, and attempt to identify inputs and protocol types on those ports.
IT: Fingerprinting TCP/IP. L'attaccante utilizza vari software per stabilire connessioni o connessioni parziali e osservare risposte idiosincratiche dal sistema operativo. Utilizzando tali risposte, tenta di indovinare il sistema operativo effettivo.
Induce errors to find informative error messages
IT: Fingerprinting TCP/IP. L'attaccante utilizza vari software per stabilire connessioni o connessioni parziali e osservare risposte idiosincratiche dal sistema operativo. Utilizzando tali risposte, tenta di indovinare il sistema operativo effettivo.

Step 2

Explore

[Survey the Application to Identify User-controllable Inputs] The attacker surveys the target application to identify all user-controllable file inputs

Step 3

Experiment

[Vary inputs, looking for malicious results] Depending on whether the application being exploited is a remote or local one, the attacker crafts the appropriate malicious input containing the path of the targeted file or other file system control syntax to be passed to the application

Step 4

Exploit

[Manipulate files accessible by the application] The attacker may steal information or directly manipulate files (delete, copy, flush, etc.)

Mitigations

Design: Enforce Principle Of Least Privilege.

Design: Input Validation. Assume That User Inputs Are Malicious. Utilize Strict Type, Character, And Encoding Enforcement.

Design: Configure The Access Control Correctly.

Design: Execute Programs With Constrained Privileges, So Parent Process Does Not Open Up Further Vulnerabilities. Ensure That All Directories, Temporary Directories And Files, And Memory Are Executing With Limited Privileges To Protect Against Remote Execution.

Design: Proxy Communication To Host, So That Communications Are Terminated At The Proxy, Sanitizing The Requests Before Forwarding To Server Host.

Implementation: Host Integrity Monitoring For Critical Files, Directories, And Processes. The Goal Of Host Integrity Monitoring Is To Be Aware When A Security Issue Has Occurred So That Incident Response And Other Forensic Activities Can Begin.

Implementation: Perform Testing Such As Pen-Testing And Vulnerability Scanning To Identify Directories, Programs, And Interfaces That Grant Direct Access To Executables.

Implementation: Use Possible Permissions On File Access When Developing And Deploying Web Applications.

Design: Run Server Interfaces With A Non-Root Account And/Or Utilize Chroot Jails Or Other Configuration Techniques To Constrain Privileges Even If Attacker Gains Some Limited Access To Commands.

Implementation: Perform Input Validation For All Remote Content, Including Remote And User-Generated Content.

Implementation: Use Indirect References Rather Than Actual File Names.

Implementation: Validate User Input By Only Accepting Known Good. Ensure All Content That Is Delivered To Client Is Sanitized Against An Acceptable Content Specification -- Using An Allowlist Approach.

CAPEC 126 Path Traversal

Description

Attack Execution Flow

Step 1

Attack Techniques

Step 2

Step 3

Step 4

Mitigations

Design: Enforce Principle Of Least Privilege.

Design: Input Validation. Assume That User Inputs Are Malicious. Utilize Strict Type, Character, And Encoding Enforcement.

Design: Configure The Access Control Correctly.

Design: Execute Programs With Constrained Privileges, So Parent Process Does Not Open Up Further Vulnerabilities. Ensure That All Directories, Temporary Directories And Files, And Memory Are Executing With Limited Privileges To Protect Against Remote Execution.

Design: Proxy Communication To Host, So That Communications Are Terminated At The Proxy, Sanitizing The Requests Before Forwarding To Server Host.

Implementation: Host Integrity Monitoring For Critical Files, Directories, And Processes. The Goal Of Host Integrity Monitoring Is To Be Aware When A Security Issue Has Occurred So That Incident Response And Other Forensic Activities Can Begin.

Implementation: Perform Testing Such As Pen-Testing And Vulnerability Scanning To Identify Directories, Programs, And Interfaces That Grant Direct Access To Executables.

Implementation: Use Possible Permissions On File Access When Developing And Deploying Web Applications.

Design: Run Server Interfaces With A Non-Root Account And/Or Utilize Chroot Jails Or Other Configuration Techniques To Constrain Privileges Even If Attacker Gains Some Limited Access To Commands.

Implementation: Perform Input Validation For All Remote Content, Including Remote And User-Generated Content.

Implementation: Use Indirect References Rather Than Actual File Names.

Implementation: Validate User Input By Only Accepting Known Good. Ensure All Content That Is Delivered To Client Is Sanitized Against An Acceptable Content Specification -- Using An Allowlist Approach.

Consequences

Security Scopes Affected

Potential Impacts

Relationships

Parent CAPECs

Child CAPECs

Resources Required

CAPEC 126 Path Traversal

Description

Attack Execution Flow

Step 1

Attack Techniques

Step 2

Step 3

Step 4

Mitigations

Design: Enforce Principle Of Least Privilege.

Design: Input Validation. Assume That User Inputs Are Malicious. Utilize Strict Type, Character, And Encoding Enforcement.

Design: Configure The Access Control Correctly.

Design: Execute Programs With Constrained Privileges, So Parent Process Does Not Open Up Further Vulnerabilities. Ensure That All Directories, Temporary Directories And Files, And Memory Are Executing With Limited Privileges To Protect Against Remote Execution.

Design: Proxy Communication To Host, So That Communications Are Terminated At The Proxy, Sanitizing The Requests Before Forwarding To Server Host.

Implementation: Host Integrity Monitoring For Critical Files, Directories, And Processes. The Goal Of Host Integrity Monitoring Is To Be Aware When A Security Issue Has Occurred So That Incident Response And Other Forensic Activities Can Begin.

Implementation: Perform Testing Such As Pen-Testing And Vulnerability Scanning To Identify Directories, Programs, And Interfaces That Grant Direct Access To Executables.

Implementation: Use Possible Permissions On File Access When Developing And Deploying Web Applications.

Design: Run Server Interfaces With A Non-Root Account And/Or Utilize Chroot Jails Or Other Configuration Techniques To Constrain Privileges Even If Attacker Gains Some Limited Access To Commands.

Implementation: Perform Input Validation For All Remote Content, Including Remote And User-Generated Content.

Implementation: Use Indirect References Rather Than Actual File Names.

Implementation: Validate User Input By Only Accepting Known Good. Ensure All Content That Is Delivered To Client Is Sanitized Against An Acceptable Content Specification -- Using An Allowlist Approach.

Consequences

Security Scopes Affected

Potential Impacts

Relationships

Parent CAPECs

Child CAPECs

Resources Required

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