CWE

CWE-271 – Privilege Dropping / Lowering Errors

Read Time:2 Minute, 6 Second

Description

The software does not drop privileges before passing control of a resource to an actor that does not have those privileges.

In some contexts, a system executing with elevated permissions will hand off a process/file/etc. to another process or user. If the privileges of an entity are not reduced, then elevated privileges are spread throughout a system and possibly to an attacker.

Modes of Introduction:

– Architecture and Design

 

Likelihood of Exploit: High

 

Related Weaknesses

CWE-269

 

Consequences

Access Control: Gain Privileges or Assume Identity

If privileges are not dropped, neither are access rights of the user. Often these rights can be prevented from being dropped.

Access Control, Non-Repudiation: Gain Privileges or Assume Identity, Hide Activities

If privileges are not dropped, in some cases the system may record actions as the user which is being impersonated rather than the impersonator.

 

Potential Mitigations

Phase: Architecture and Design

Description: 

Phase: Architecture and Design, Operation

Description: 

Very carefully manage the setting, management, and handling of privileges. Explicitly manage trust zones in the software.

Phase: Architecture and Design

Description: 

Consider following the principle of separation of privilege. Require multiple conditions to be met before permitting access to a system resource.

CVE References

  • CVE-2000-1213
    • Program does not drop privileges after acquiring the raw socket.
  • CVE-2001-0559
    • Setuid program does not drop privileges after a parsing error occurs, then calls another program to handle the error.
  • CVE-2001-0787
    • Does not drop privileges in related groups when lowering privileges.
  • CVE-2002-0080
    • Does not drop privileges in related groups when lowering privileges.
  • CVE-2001-1029
    • Does not drop privileges before determining access to certain files.
  • CVE-1999-0813
    • Finger daemon does not drop privileges when executing programs on behalf of the user being fingered.
  • CVE-1999-1326
    • FTP server does not drop privileges if a connection is aborted during file transfer.
  • CVE-2004-2504
    • Windows program running as SYSTEM does not drop privileges before executing other programs (many others like this, especially involving the Help facility).
  • CVE-2004-0213
    • Utility Manager launches winhlp32.exe while running with raised privileges, which allows local users to gain system privileges.
  • CVE-2004-0806
    • Setuid program does not drop privileges before executing program specified in an environment variable.
  • CVE-2004-0828
    • Setuid program does not drop privileges before processing file specified on command line.
  • CVE-2004-2070
    • Service on Windows does not drop privileges before using “view file” option, allowing code execution.