Reliance on Obfuscation or Encryption of Security-Relevant Inputs without Integrity CheckingID: 649 | Date: (C)2012-05-14 (M)2022-10-10 |
Type: weakness | Status: INCOMPLETE |
Abstraction Type: Base |
Description
The software uses obfuscation or encryption of inputs that
should not be mutable by an external actor, but the software does not use
integrity checks to detect if those inputs have been
modified.
Extended DescriptionWhen an application relies on obfuscation or incorrectly applied / weak
encryption to protect client-controllable tokens or parameters, that may
have an effect on the user state, system state, or some decision made on the
server. Without protecting the tokens/parameters for integrity, the
application is vulnerable to an attack where an adversary blindly traverses
the space of possible values of the said token/parameter in order to attempt
to gain an advantage. The goal of the attacker is to find another admissible
value that will somehow elevate his or her privileges in the system,
disclose information or change the behavior of the system in some way
beneficial to the attacker. If the application does not protect these
critical tokens/parameters for integrity, it will not be able to determine
that these values have been tampered with. Measures that are used to protect
data for confidentiality should not be relied upon to provide the integrity
service.
Enabling Factors for ExploitationThe application uses client controllable tokens/parameters in order to
make decisions on the server side about user state, system state or other
decisions related to the functionality of the application.The application does not protect client controllable tokens/parameters for
integrity and thus not able to catch tampering.
Likelihood of Exploit: High
Applicable PlatformsLanguage Class: All
Time Of Introduction
- Architecture and Design
- Implementation
Related Attack Patterns
Common Consequences
Scope | Technical Impact | Notes |
---|
Integrity | Unexpected state | The inputs could be modified without detection, causing the software
to have unexpected system state or make incorrect security
decisions. |
Detection MethodsNone
Potential Mitigations
Phase | Strategy | Description | Effectiveness | Notes |
---|
Architecture and Design | | Protect important client controllable tokens/parameters for integrity
using PKI methods (i.e. digital signatures) or other means, and checks
for integrity on the server side. | | |
Architecture and Design | | Repeated requests from a particular user that include invalid values
of tokens/parameters (those that should not be changed manually by
users) should result in the user account lockout. | | |
Architecture and Design | | Client side tokens/parameters should not be such that it would be
easy/predictable to guess another valid state. | | |
Architecture and Design | | Obfuscation should not be relied upon. If encryption is used, it needs
to be properly applied (i.e. proven algorithm and implementation, use
padding, use random initialization vector, user proper encryption mode).
Even with proper encryption where the ciphertext does not leak
information about the plaintext or reveal its structure, compromising
integrity is possible (although less likely) without the provision of
the integrity service. | | |
Relationships
Related CWE | Type | View | Chain |
---|
CWE-649 ChildOf CWE-907 | Category | CWE-888 | |
Demonstrative ExamplesNone
Observed Examples
- CVE-2005-0039 : An IPSec configuration does not perform integrity checking of the IPSec packet as the result of either not configuring ESP properly to support the integrity service or using AH improperly. In either case, the security gateway receiving the IPSec packet would not validate the integrity of the packet to ensure that it was not changed. Thus if the packets were intercepted the attacker could undetectably change some of the bits in the packets. The meaningful bit flipping was possible due to the known weaknesses in the CBC encryption mode. Since the attacker knew the structure of the packet, he or she was able (in one variation of the attack) to use bit flipping to change the destination IP of the packet to the destination machine controlled by the attacker. And so the destination security gateway would decrypt the packet and then forward the plaintext to the machine controlled by the attacker. The attacker could then read the original message. For instance if VPN was used with the vulnerable IPSec configuration the attacker could read the victim's e-mail. This vulnerability demonstrates the need to enforce the integrity service properly when critical data could be modified by an attacker. This problem might have also been mitigated by using an encryption mode that is not susceptible to bit flipping attacks, but the preferred mechanism to address this problem still remains message verification for integrity. While this attack focuses on the network layer and requires a man in the middle scenario, the situation is not much different at the software level where an attacker can modify tokens/parameters used by the application.
For more examples, refer to CVE relations in the bottom box.
White Box Definitions None
Black Box Definitions None
Taxynomy MappingsNone
References:None