| Attack Pattern ID | Pattern Abstraction: Standard 38 |
| Typical Severity | Very High |
| Description | Summary
This attack loads a malicious resource into a program's standard path used to bootstrap and/or provide contextual information for a program like a path variable or classpath. J2EE applications and other component based applications that are built from mutliple binaries can have very long list of dependencies to execute. If one of these libraries and/or references is controllable by the attacker then application controls can be circumvented by the attacker.
A standard UNIX path looks similar to this
/bin:/sbin:/usr/bin:/usr/local/bin:/usr/sbin
If the attacker modifies the path variable to point to a locale that includes malicious resources then the user unwittingly can execute commands on the attacker's behalf:
/evildir/bin:/sbin:/usr/bin:/usr/local/bin:/usr/sbin
This is a form of usurping control of the program and the attack can be done on the classpath, database resources, or any other resources built from compound parts. At runtime detection and blocking of this attack is nearly impossible, because the configuration allows execution.
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| Attack Prerequisites |
The attacker must be able to write to redirect search paths on the victim host.
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| Typical Likelihood of Exploit |
High
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| Methods of Attack | - Modification of Resources
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| Examples-Instances | Description
This attack can be accomplished in two ways. An attacker can insert a malicious program into the path or classpath so that when a known command is executed then the system instead executes the trojans. Another method is to redirect commands by aliasing one legitimate command to another to create unexpected results. the Unix command "rm" could be aliased to "mv" and move all files the victim thinks they are deleting to a directory the attacker controls. In a Unix shell .profile setting
alias rm=mv /usr/home/attacker
In this case the attacker retains a copy of all the files the victim attempts to remove.
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| Attacker Skill or Knowledge Required |
Low → to identify and execute against an overprivileged system interface
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| Solutions and Mitigations |
Design: Enforce principle of least privilege
Design: Ensure that the program's compound parts, including all system dependencies, classpath, path, and so on, are secured to the same or higher level assurance as the program
Implementation: Host integrity monitoring
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| Attack Motivation-Consequences | - Run Arbitrary Code
- Privilege Escalation
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| Context Description |
“Attack Pattern: Make Use of Configuration File Search Paths
If you place a copy of the configuration file into a previously empty location, the target program may find your version first and forgo any further searching. Most programs are not aware of security, so no check will be made against the owner of the file. The UNIX environment variable for PATH will sometimes specify that a program should look in multiple directories for a given file. Check these directories to determine whether you can sneak a Trojan file into the target."
[Hoglund and McGraw 04]
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| Related Weaknesses | | CWE-ID | Weakness Name | Weakness Relationship Type |
|---|
| 426 | Untrusted Search Path | Targeted | | 427 | Uncontrolled Search Path Element | Targeted | | 428 | Unquoted Search Path or Element | Secondary |
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| Related Attack Patterns | | ID | Name | Relationship Type | Relationship Description |
|---|
| 13 | Subverting Environment Variable Values | More Detailed | |
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| Purpose | Exploitation |
| CIA Impact | | Confidentiality Impact | Integrity Impact | Availability Impact |
|---|
| Medium | Medium | Medium |
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| Technical Context | | Architectural Paradigm | Framework | Platform | Language |
|---|
| All | All | All | All |
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| References |
G. Hoglund and G. McGraw. Exploiting Software: How to Break Code. Addison-Wesley, February 2004.
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| Source | | Submission(s) |
|---|
| Submitter | Organization | Date | Comment |
|---|
| G. Hoglund and G. McGraw. Exploiting Software: How to Break Code. Addison-Wesley, February 2004. | Cigital, Inc | 2007-01-01 | |
| Modification(s) |
|---|
| Modifier | Organization | Date | Comment |
|---|
| Gunnar Peterson | Cigital, Inc | 2007-02-28 | Fleshed out content to CAPEC schema from the original descriptions in "Exploiting Software" | | Sean Barnum | Cigital, Inc | 2007-03-09 | Review and revise | | Richard Struse | VOXEM, Inc | 2007-03-26 | Review and feedback leading to changes in Name and Related Attack Patterns | | Sean Barnum | Cigital, Inc | 2007-04-13 | Modified pattern content according to review and feedback |
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