CAPEC-35: Leverage Executable Code in Non-Executable Files
Attack Pattern ID: 35
Abstraction: Detailed
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Description
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.
Likelihood Of Attack
High
Typical Severity
Very High
Relationships
This table shows the other attack patterns and high level categories that are related to this attack pattern. These relationships are defined as ChildOf and ParentOf, and give insight to similar items that may exist at higher and lower levels of abstraction. In addition, relationships such as CanFollow, PeerOf, and CanAlsoBe are defined to show similar attack patterns that the user may want to explore.
Nature
Type
ID
Name
ChildOf
Standard Attack Pattern - A standard level attack pattern in CAPEC is focused on a specific methodology or technique used in an attack. It is often seen as a singular piece of a fully executed attack. A standard attack pattern is meant to provide sufficient details to understand the specific technique and how it attempts to accomplish a desired goal. A standard level attack pattern is a specific type of a more abstract meta level attack pattern.
Standard Attack Pattern - A standard level attack pattern in CAPEC is focused on a specific methodology or technique used in an attack. It is often seen as a singular piece of a fully executed attack. A standard attack pattern is meant to provide sufficient details to understand the specific technique and how it attempts to accomplish a desired goal. A standard level attack pattern is a specific type of a more abstract meta level attack pattern.
Standard Attack Pattern - A standard level attack pattern in CAPEC is focused on a specific methodology or technique used in an attack. It is often seen as a singular piece of a fully executed attack. A standard attack pattern is meant to provide sufficient details to understand the specific technique and how it attempts to accomplish a desired goal. A standard level attack pattern is a specific type of a more abstract meta level attack pattern.
The attacker must have the ability to modify non-executable files consumed by the target software.
Skills Required
[Level: Low]
To identify and execute against an over-privileged system interface
Resources Required
Ability to communicate synchronously or asynchronously with server that publishes an over-privileged directory, program, or interface. Optionally, ability to capture output directly through synchronous communication or other method such as FTP.
Consequences
This table specifies different individual consequences associated with the attack pattern. The Scope identifies the security property that is violated, while the Impact describes the negative technical impact that arises if an adversary succeeds in their attack. The Likelihood provides information about how likely the specific consequence is expected to be seen relative to the other consequences in the list. For example, there may be high likelihood that a pattern will be used to achieve a certain impact, but a low likelihood that it will be exploited to achieve a different impact.
Scope
Impact
Likelihood
Confidentiality
Integrity
Availability
Execute Unauthorized Commands
Integrity
Modify Data
Confidentiality
Access Control
Authorization
Gain Privileges
Mitigations
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 pen-testing 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.
Example Instances
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 fingerprint 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.
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/)
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.
< security-constraint>
<description>Security processing rules for admin screens</description> <url-pattern>/admin/*</url-pattern> <http-method>POST</http-method> <http-method>GET</http-method>
The server trusts its configuration file to be correct, but when they are manipulated, the attacker gains full control.
Related Weaknesses
A Related Weakness relationship associates a weakness with this attack pattern. Each association implies a weakness that must exist for a given attack to be successful. If multiple weaknesses are associated with the attack pattern, then any of the weaknesses (but not necessarily all) may be present for the attack to be successful. Each related weakness is identified by a CWE identifier.
CAPEC mappings to ATT&CK techniques leverage an inheritance model to streamline and minimize direct CAPEC/ATT&CK mappings. Inheritance of a mapping is indicated by text stating that the parent CAPEC has relevant ATT&CK mappings. Note that the ATT&CK Enterprise Framework does not use an inheritance model as part of the mapping to CAPEC.
Relevant to the ATT&CK taxonomy mapping (also see parent)
Description
This table shows the other attack patterns and high level categories that are related to this attack pattern. These relationships are defined as ChildOf and ParentOf, and give insight to similar items that may exist at higher and lower levels of abstraction. In addition, relationships such as CanFollow, PeerOf, and CanAlsoBe are defined to show similar attack patterns that the user may want to explore.
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