CWE-36: Absolute Path Traversal

Description

The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize absolute path sequences such as "/abs/path" that can resolve to a location that is outside of that directory.

Extended Description

This allows attackers to traverse the file system to access files or directories that are outside of the restricted directory.

ThreatScore

Threat Mapped score: 0.0

Industry: Finiancial

Threat priority: Unclassified

Observed Examples (CVEs)

CVE: CVE-2022-31503

Python package constructs filenames using an unsafe os.path.join call on untrusted input, allowing absolute path traversal because os.path.join resets the pathname to an absolute path that is specified as part of the input.
CVE: CVE-2002-1345

Multiple FTP clients write arbitrary files via absolute paths in server responses
CVE: CVE-2001-1269

ZIP file extractor allows full path
CVE: CVE-2002-1818

Path traversal using absolute pathname
CVE: CVE-2002-1913

Path traversal using absolute pathname
CVE: CVE-2005-2147

Path traversal using absolute pathname
CVE: CVE-2000-0614

Arbitrary files may be overwritten via compressed attachments that specify absolute path names for the decompressed output.
CVE: CVE-1999-1263

Mail client allows remote attackers to overwrite arbitrary files via an e-mail message containing a uuencoded attachment that specifies the full pathname for the file to be modified.
CVE: CVE-2003-0753

Remote attackers can read arbitrary files via a full pathname to the target file in config parameter.
CVE: CVE-2002-1525

Remote attackers can read arbitrary files via an absolute pathname.
CVE: CVE-2001-0038

Remote attackers can read arbitrary files by specifying the drive letter in the requested URL.
CVE: CVE-2001-0255

FTP server allows remote attackers to list arbitrary directories by using the "ls" command and including the drive letter name (e.g. C:) in the requested pathname.
CVE: CVE-2001-0933

FTP server allows remote attackers to list the contents of arbitrary drives via a ls command that includes the drive letter as an argument.
CVE: CVE-2002-0466

Server allows remote attackers to browse arbitrary directories via a full pathname in the arguments to certain dynamic pages.
CVE: CVE-2002-1483

Remote attackers can read arbitrary files via an HTTP request whose argument is a filename of the form "C:" (Drive letter), "//absolute/path", or ".." .
CVE: CVE-2004-2488

FTP server read/access arbitrary files using "C:\" filenames
CVE: CVE-2001-0687

FTP server allows a remote attacker to retrieve privileged web server system information by specifying arbitrary paths in the UNC format (\\computername\sharename).

Related Attack Patterns (CAPEC)

CAPEC-597

Attack TTPs

N/A

Modes of Introduction

Phase	Note
Implementation	N/A

Common Consequences

Impact: Execute Unauthorized Code or Commands — Notes: The attacker may be able to create or overwrite critical files that are used to execute code, such as programs or libraries.
Impact: Modify Files or Directories — Notes: The attacker may be able to overwrite or create critical files, such as programs, libraries, or important data. If the targeted file is used for a security mechanism, then the attacker may be able to bypass that mechanism. For example, appending a new account at the end of a password file may allow an attacker to bypass authentication.
Impact: Read Files or Directories — Notes: The attacker may be able read the contents of unexpected files and expose sensitive data. If the targeted file is used for a security mechanism, then the attacker may be able to bypass that mechanism. For example, by reading a password file, the attacker could conduct brute force password guessing attacks in order to break into an account on the system.
Impact: DoS: Crash, Exit, or Restart — Notes: The attacker may be able to overwrite, delete, or corrupt unexpected critical files such as programs, libraries, or important data. This may prevent the product from working at all and in the case of a protection mechanisms such as authentication, it has the potential to lockout every user of the product.

Potential Mitigations

None listed.

Applicable Platforms

None (Not Language-Specific, Undetermined)

Demonstrative Examples

Intro: In the example below, the path to a dictionary file is read from a system property and used to initialize a File object.

Body: However, the path is not validated or modified to prevent it from containing relative or absolute path sequences before creating the File object. This allows anyone who can control the system property to determine what file is used. Ideally, the path should be resolved relative to some kind of application or user home directory.

String filename = System.getProperty("com.domain.application.dictionaryFile"); File dictionaryFile = new File(filename);

Intro: This script intends to read a user-supplied file from the current directory. The user inputs the relative path to the file and the script uses Python's os.path.join() function to combine the path to the current working directory with the provided path to the specified file. This results in an absolute path to the desired file. If the file does not exist when the script attempts to read it, an error is printed to the user.

Body: However, if the user supplies an absolute path, the os.path.join() function will discard the path to the current working directory and use only the absolute path provided. For example, if the current working directory is /home/user/documents, but the user inputs /etc/passwd, os.path.join() will use only /etc/passwd, as it is considered an absolute path. In the above scenario, this would cause the script to access and read the /etc/passwd file.

import os import sys def main(): filename = sys.argv[1] path = os.path.join(os.getcwd(), filename) try: with open(path, 'r') as f: file_data = f.read() except FileNotFoundError as e: print("Error - file not found") main()

Notes

No notes available.

← Back to CWE list