CWE-1314: Missing Write Protection for Parametric Data Values
Weakness ID: 1314
Vulnerability Mapping:ALLOWEDThis CWE ID may be used to map to real-world vulnerabilities Abstraction:
BaseBase - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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Description
The device does not write-protect the parametric data values for sensors that scale the sensor value, allowing untrusted software to manipulate the apparent result and potentially damage hardware or cause operational failure.
Extended Description
Various sensors are used by hardware to detect any devices operating outside of the design limits. The threshold limit values are set by hardware fuses or trusted software such as the BIOS. These limits may be related to thermal, power, voltage, current, and frequency. Hardware mechanisms may be used to protect against alteration of the threshold limit values by untrusted software.
The limit values are generally programmed in standard units for the type of value being read. However, the hardware-sensor blocks may report the settings in different units depending upon sensor design and operation. The raw sensor output value is converted to the desired units using a scale conversion based on the parametric data programmed into the sensor. The final converted value is then compared with the previously programmed limits.
While the limit values are usually protected, the sensor parametric data values may not be. By changing the parametric data, safe operational limits may be bypassed.
Common Consequences
This table specifies different individual consequences
associated with the weakness. The Scope identifies the application security area that is
violated, while the Impact describes the negative technical impact that arises if an
adversary succeeds in exploiting this weakness. 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 weakness will be
exploited to achieve a certain impact, but a low likelihood that it will be exploited to
achieve a different impact.
Sensor value manipulation, particularly thermal or power, may allow physical damage to occur or disabling of the device by a false fault shutdown causing a Denial-Of-Service.
Potential Mitigations
Phase(s)
Mitigation
Architecture and Design
Access controls for sensor blocks should ensure that only trusted software is allowed to change threshold limits and sensor parametric data.
Effectiveness: High
Relationships
This table shows the weaknesses and high level categories that are related to this
weakness. These relationships are defined as ChildOf, ParentOf, MemberOf and give insight to
similar items that may exist at higher and lower levels of abstraction. In addition,
relationships such as PeerOf and CanAlsoBe are defined to show similar weaknesses that the user
may want to explore.
Relevant to the view "Research Concepts" (View-1000)
Nature
Type
ID
Name
ChildOf
Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.
Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
Missing Protection Mechanism for Alternate Hardware Interface
Modes
Of Introduction
The different Modes of Introduction provide information
about how and when this
weakness may be introduced. The Phase identifies a point in the life cycle at which
introduction
may occur, while the Note provides a typical scenario related to introduction during the
given
phase.
Phase
Note
Architecture and Design
The lack of a requirement to protect parametric values may contribute to this weakness.
Implementation
The lack of parametric value protection may be a cause of this weakness.
Applicable Platforms
This listing shows possible areas for which the given
weakness could appear. These
may be for specific named Languages, Operating Systems, Architectures, Paradigms,
Technologies,
or a class of such platforms. The platform is listed along with how frequently the given
weakness appears for that instance.
Languages
Class: Not Language-Specific
(Undetermined Prevalence)
Operating Systems
Class: Not OS-Specific
(Undetermined Prevalence)
Architectures
Class: Not Architecture-Specific
(Undetermined Prevalence)
Technologies
Sensor Hardware
(Undetermined Prevalence)
Demonstrative Examples
Example 1
Malicious software executes instructions to increase power consumption to the highest possible level while causing the clock frequency to increase to its maximum value.
Such a program executing for an extended period of time would likely overheat the device, possibly resulting in permanent damage to the device.
A ring, oscillator-based temperature sensor will generally report the sensed value as
oscillator frequency rather than degrees centigrade. The temperature sensor will have
calibration values that are used to convert the detected frequency into the corresponding temperature in degrees centigrade.
Consider a SoC design where the critical maximum temperature limit is set in fuse values to 100C and
is not modifiable by software. If the scaled thermal sensor output equals or exceeds this limit, the system is commanded to shut itself down.
The thermal sensor calibration values are programmable through registers that are exposed to system software.
These registers allow software to affect the converted temperature output such that the output will never exceed the maximum temperature limit.
(bad code)
Example Language: Other
The sensor frequency value is scaled by applying the function:
Sensed Temp = a + b * Sensor Freq
where a and b are the programmable calibration data coefficients. Software sets a and b to zero ensuring the sensed
temperature is always zero.
This weakness may be addressed by preventing access to a and b.
(good code)
Example Language: Other
The sensor frequency value is scaled by applying the function:
Sensed Temp = a + b * Sensor Freq
where a and b are the programmable calibration data coefficients. Untrusted software is prevented from changing the values of either a or b,
preventing this method of manipulating the temperature.
Selected Observed
Examples
Note: this is a curated list of examples for users to understand the variety of ways in which this
weakness can be introduced. It is not a complete list of all CVEs that are related to this CWE entry.
Kernel can inject faults in computations during the execution of TrustZone leading to information disclosure in Snapdragon Auto, Snapdragon Compute, Snapdragon Connectivity, Snapdragon Consumer Electronics Connectivity, Snapdragon Consumer IOT, Snapdragon Industrial IOT, Snapdragon IoT, Snapdragon Mobile, Snapdragon Voice and Music, Snapdragon Wearables, Snapdragon Wired Infrastructure and Networking.
Memberships
This MemberOf Relationships table shows additional CWE Categories and Views that
reference this weakness as a member. This information is often useful in understanding where a
weakness fits within the context of external information sources.
Nature
Type
ID
Name
MemberOf
Category - a CWE entry that contains a set of other entries that share a common characteristic.
(this CWE ID may be used to map to real-world vulnerabilities)
Reason
Acceptable-Use
Rationale
This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
Comments
Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.
Description
This table specifies different individual consequences
associated with the weakness. The Scope identifies the application security area that is
violated, while the Impact describes the negative technical impact that arises if an
adversary succeeds in exploiting this weakness. 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 weakness will be
exploited to achieve a certain impact, but a low likelihood that it will be exploited to
achieve a different impact.
