Leverage Executable Code in Nonexecutable Files |
Attack Pattern ID: 35 (Standard Attack Pattern Completeness: Complete) | Typical Severity: Very High | Status: Draft |
Summary
An attack of this type exploits a system's trust in configuration and resource files, when the executable loads the resource (such as an image file or configuration file) the attacker has modified the file to either execute malicious code directly or manipulate the target process (e.g. application server) to execute based on the malicious configuration parameters. Since systems are increasingly interrelated mashing up resources from local and remote sources the possibility of this attack occurring is high.
The attack can be directed at a client system, such as causing buffer overrun through loading seemingly benign image files, as in Microsoft Security Bulletin MS04-028 where specially crafted JPEG files could cause a buffer overrun once loaded into the browser. Another example targets clients reading pdf files. In this case the attacker simply appends javascript to the end of a legitimate url for a pdf (http://www.gnucitizen.org/blog/danger-danger-danger/)
http://path/to/pdf/file.pdf#whatever_name_you_want=javascript:your_code_here
The client assumes that they are reading a pdf, but the attacker has modified the resource and loaded executable javascript into the client's browser process.
The attack can also target server processes. The attacker edits the resource or configuration file, for example a web.xml file used to configure security permissions for a J2EE app server, adding role name "public" grants all users with the public role the ability to use the administration functionality.
The server trusts its configuration file to be correct, but when they are manipulated, the attacker gains full control.
The attacker must have the ability to modify nonexecutable files consumed by the target software.
Description
Virtually any system that relies on configuration files for runtime behavior is open to this attack vector. The configuration files are frequently stored in predictable locations, so an attacker that can fingerpint a server process such as a web server or database server can quickly identify the likely locale where the configuration is stored. And this is of course not limited to server processes. Unix shells rely on profile files to store environment variables, search paths for programs and so on. If the aliases are changed, then a standard Unix "cp" command can be rerouted to "rm" or other standard command so the user's intention is subverted.
Skill or Knowledge Level: Low
To identify and execute against an overprivileged system interface
Ability to communicate synchronously or asynchronously with server that publishes an overprivileged directory, program, or itnerface. Optionally, ability to capture output directly through synchronous communication or other method such as FTP.
Design: Enforce principle of least privilege
Design: Run server interfaces with a non-root account and/or utilize chroot jails or other configuration techniques to constrain privileges even if attacker gains some limited access to commands.
Implementation: Perform testing such as pentesting and vulnerability scanning to identify directories, programs, and interfaces that grant direct access to executables.
Implementation: Implement host integrity monitoring to detect any unwanted altering of configuration files.
Implementation: Ensure that files that are not required to execute, such as configuration files, are not over-privileged, i.e. not allowed to execute.
Enables attacker to execute server side code with any commands that the program owner has privileges to.
CWE-ID | Weakness Name | Weakness Relationship Type |
---|---|---|
94 | Failure to Control Generation of Code ('Code Injection') | Targeted |
96 | Improper Neutralization of Directives in Statically Saved Code ('Static Code Injection') | Targeted |
95 | Improper Sanitization of Directives in Dynamically Evaluated Code ('Eval Injection') | Targeted |
97 | Failure to Sanitize Server-Side Includes (SSI) Within a Web Page | Targeted |
272 | Least Privilege Violation | Secondary |
59 | Improper Link Resolution Before File Access ('Link Following') | Secondary |
282 | Improper Ownership Management | Secondary |
275 | Permission Issues | Secondary |
264 | Permissions, Privileges, and Access Controls | Secondary |
270 | Privilege Context Switching Error | Secondary |
714 | OWASP Top Ten 2007 Category A3 - Malicious File Execution | Targeted |
Vulnerability ID | Relationship Description |
---|---|
Microsoft Security Bulletin MS04-028 | Buffer Overrun in JPEG Processing (GDI+) Could Allow Code Execution |
Nature | Type | ID | Name | Description | View(s) this relationship pertains to |
---|---|---|---|---|---|
PeerOf | Attack Pattern | 23 | File System Function Injection, Content Based | Mechanism of Attack1000 | |
PeerOf | Attack Pattern | 75 | Manipulating Writeable Configuration Files | Mechanism of Attack1000 | |
ChildOf | Attack Pattern | 165 | File Manipulation | Mechanism of Attack (primary)1000 | |
PeerOf | Attack Pattern | 44 | Overflow Binary Resource File | Mechanism of Attack1000 |
Submissions | ||||
---|---|---|---|---|
Submitter | Organization | Date | ||
G. Hoglund and G. McGraw. Exploiting Software: How to Break Code. Addison-Wesley, February 2004. | Cigital, Inc | 2007-01-01 |
Modifications | |||||
---|---|---|---|---|---|
Modifier | Organization | Date | Comments | ||
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 Related Attack Patterns | ||
Sean Barnum | Cigital, Inc | 2007-04-13 | Modified pattern content according to review and feedback |