The product searches for critical resources using an externally-supplied search path that can point to resources that are not under the product's direct control.
This might allow attackers to execute their own programs, access unauthorized data files, or modify configuration in unexpected ways. If the product uses a search path to locate critical resources such as programs, then an attacker could modify that search path to point to a malicious program, which the targeted product would then execute. The problem extends to any type of critical resource that the product trusts. Some of the most common variants of untrusted search path are: In various UNIX and Linux-based systems, the PATH environment variable may be consulted to locate executable programs, and LD_PRELOAD may be used to locate a separate library. In various Microsoft-based systems, the PATH environment variable is consulted to locate a DLL, if the DLL is not found in other paths that appear earlier in the search order.
Threat Mapped score: 1.8
Industry: Finiancial
Threat priority: P4 - Informational (Low)
CVE: CVE-1999-1120
Application relies on its PATH environment variable to find and execute program.
CVE: CVE-2008-1810
Database application relies on its PATH environment variable to find and execute program.
CVE: CVE-2007-2027
Chain: untrusted search path enabling resultant format string by loading malicious internationalization messages.
CVE: CVE-2008-3485
Untrusted search path using malicious .EXE in Windows environment.
CVE: CVE-2008-2613
setuid program allows compromise using path that finds and loads a malicious library.
CVE: CVE-2008-1319
Server allows client to specify the search path, which can be modified to point to a program that the client has uploaded.
| Phase | Note |
|---|---|
| Implementation | N/A |
Intro: This program is intended to execute a command that lists the contents of a restricted directory, then performs other actions. Assume that it runs with setuid privileges in order to bypass the permissions check by the operating system.
Body: This code may look harmless at first, since both the directory and the command are set to fixed values that the attacker can't control. The attacker can only see the contents for DIR, which is the intended program behavior. Finally, the programmer is also careful to limit the code that executes with raised privileges.
#define DIR "/restricted/directory" char cmd[500]; sprintf(cmd, "ls -l %480s", DIR); /* Raise privileges to those needed for accessing DIR. */ RaisePrivileges(...); system(cmd); DropPrivileges(...); ...Intro: The following code from a system utility uses the system property APPHOME to determine the directory in which it is installed and then executes an initialization script based on a relative path from the specified directory.
Body: The code above allows an attacker to execute arbitrary commands with the elevated privilege of the application by modifying the system property APPHOME to point to a different path containing a malicious version of INITCMD. Because the program does not validate the value read from the environment, if an attacker can control the value of the system property APPHOME, then they can fool the application into running malicious code and take control of the system.
... String home = System.getProperty("APPHOME"); String cmd = home + INITCMD; java.lang.Runtime.getRuntime().exec(cmd); ...Intro: This code prints all of the running processes belonging to the current user.
Body: If invoked by an unauthorized web user, it is providing a web page of potentially sensitive information on the underlying system, such as command-line arguments (CWE-497). This program is also potentially vulnerable to a PATH based attack (CWE-426), as an attacker may be able to create malicious versions of the ps or grep commands. While the program does not explicitly raise privileges to run the system commands, the PHP interpreter may by default be running with higher privileges than users.
//assume getCurrentUser() returns a username that is guaranteed to be alphanumeric (avoiding CWE-78) $userName = getCurrentUser(); $command = 'ps aux | grep ' . $userName; system($command);Intro: The following code is from a web application that allows users access to an interface through which they can update their password on the system. In this environment, user passwords can be managed using the Network Information System (NIS), which is commonly used on UNIX systems. When performing NIS updates, part of the process for updating passwords is to run a make command in the /var/yp directory. Performing NIS updates requires extra privileges.
Body: The problem here is that the program does not specify an absolute path for make and does not clean its environment prior to executing the call to Runtime.exec(). If an attacker can modify the $PATH variable to point to a malicious binary called make and cause the program to be executed in their environment, then the malicious binary will be loaded instead of the one intended. Because of the nature of the application, it runs with the privileges necessary to perform system operations, which means the attacker's make will now be run with these privileges, possibly giving the attacker complete control of the system.
... System.Runtime.getRuntime().exec("make"); ...