CWE-61—UNIX Symbolic Link (Symlink) Following

Weakness Name

UNIX Symbolic Link (Symlink) Following

Description

The product, when opening a file or directory, does not sufficiently account for when the file is a symbolic link that resolves to a target outside of the intended control sphere. This could allow an attacker to cause the product to operate on unauthorized files.

A product that allows UNIX symbolic links (symlink) as part of paths whether in internal code or through user input can allow an attacker to spoof the symbolic link and traverse the file system to unintended locations or access arbitrary files. The symbolic link can permit an attacker to read/write/corrupt a file that they originally did not have permissions to access.

Common Consequences

Scope:

Confidentiality, Integrity

Impact:

Read Files or Directories, Modify Files or Directories

Related Weaknesses

• CWE-59Improper Link Resolution Before File Access ('Link Following')Medium
• CWE-340Generation of Predictable Numbers or Identifiers
• CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')Medium
• CWE-386Symbolic Name not Mapping to Correct Object
• CWE-732Incorrect Permission Assignment for Critical ResourceHigh