Vulnerabilities > CVE-2023-46851 - External Control of File Name or Path vulnerability in Apache Allura

047910
CVSS 4.9 - MEDIUM
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
HIGH
Confidentiality impact
HIGH
Integrity impact
NONE
Availability impact
NONE
network
low complexity
apache
CWE-73

Summary

Allura Discussion and Allura Forum importing does not restrict URL values specified in attachments. Project administrators can run these imports, which could cause Allura to read local files and expose them.  Exposing internal files then can lead to other exploits, like session hijacking, or remote code execution. This issue affects Apache Allura from 1.0.1 through 1.15.0. Users are recommended to upgrade to version 1.16.0, which fixes the issue.  If you are unable to upgrade, set "disable_entry_points.allura.importers = forge-tracker, forge-discussion" in your .ini config file.

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Subverting Environment Variable Values
    The attacker directly or indirectly modifies environment variables used by or controlling the target software. The attacker's goal is to cause the target software to deviate from its expected operation in a manner that benefits the attacker.
  • Leverage Alternate Encoding
    This attack leverages the possibility to encode potentially harmful input and submit it to applications not expecting or effective at validating this encoding standard making input filtering difficult.
  • Using Slashes and URL Encoding Combined to Bypass Validation Logic
    This attack targets the encoding of the URL combined with the encoding of the slash characters. An attacker can take advantage of the multiple way of encoding an URL and abuse the interpretation of the URL. An URL may contain special character that need special syntax handling in order to be interpreted. Special characters are represented using a percentage character followed by two digits representing the octet code of the original character (%HEX-CODE). For instance US-ASCII space character would be represented with %20. This is often referred as escaped ending or percent-encoding. Since the server decodes the URL from the requests, it may restrict the access to some URL paths by validating and filtering out the URL requests it received. An attacker will try to craft an URL with a sequence of special characters which once interpreted by the server will be equivalent to a forbidden URL. It can be difficult to protect against this attack since the URL can contain other format of encoding such as UTF-8 encoding, Unicode-encoding, etc.
  • URL Encoding
    This attack targets the encoding of the URL. An attacker can take advantage of the multiple way of encoding an URL and abuse the interpretation of the URL. An URL may contain special character that need special syntax handling in order to be interpreted. Special characters are represented using a percentage character followed by two digits representing the octet code of the original character (%HEX-CODE). For instance US-ASCII space character would be represented with %20. This is often referred as escaped ending or percent-encoding. Since the server decodes the URL from the requests, it may restrict the access to some URL paths by validating and filtering out the URL requests it received. An attacker will try to craft an URL with a sequence of special characters which once interpreted by the server will be equivalent to a forbidden URL. It can be difficult to protect against this attack since the URL can contain other format of encoding such as UTF-8 encoding, Unicode-encoding, etc. The attacker could also subvert the meaning of the URL string request by encoding the data being sent to the server through a GET request. For instance an attacker may subvert the meaning of parameters used in a SQL request and sent through the URL string (See Example section).
  • Manipulating Input to File System Calls
    An attacker manipulates inputs to the target software which the target software passes to file system calls in the OS. The goal is to gain access to, and perhaps modify, areas of the file system that the target software did not intend to be accessible.