CWE-656: Reliance on Security Through Obscurity

Description

The product uses a protection mechanism whose strength depends heavily on its obscurity, such that knowledge of its algorithms or key data is sufficient to defeat the mechanism.

Extended Description

This reliance on "security through obscurity" can produce resultant weaknesses if an attacker is able to reverse engineer the inner workings of the mechanism. Note that obscurity can be one small part of defense in depth, since it can create more work for an attacker; however, it is a significant risk if used as the primary means of protection.

ThreatScore

Threat Mapped score: 0.0

Industry: Finiancial

Threat priority: Unclassified

Observed Examples (CVEs)

CVE: CVE-2006-6588

Reliance on hidden form fields in a web application. Many web application vulnerabilities exist because the developer did not consider that "hidden" form fields can be processed using a modified client.
CVE: CVE-2006-7142

Hard-coded cryptographic key stored in executable program.
CVE: CVE-2005-4002

Hard-coded cryptographic key stored in executable program.
CVE: CVE-2006-4068

Hard-coded hashed values for username and password contained in client-side script, allowing brute-force offline attacks.

Related Attack Patterns (CAPEC)

N/A

Attack TTPs

N/A

Modes of Introduction

Phase	Note
Architecture and Design	N/A
Implementation	REALIZATION: This weakness is caused during implementation of an architectural security tactic.

Common Consequences

Impact: Other — Notes: The security mechanism can be bypassed easily.

Potential Mitigations

Architecture and Design: Always consider whether knowledge of your code or design is sufficient to break it. Reverse engineering is a highly successful discipline, and financially feasible for motivated adversaries. Black-box techniques are established for binary analysis of executables that use obfuscation, runtime analysis of proprietary protocols, inferring file formats, and others. (N/A)
Architecture and Design: When available, use publicly-vetted algorithms and procedures, as these are more likely to undergo more extensive security analysis and testing. This is especially the case with encryption and authentication. (N/A)

Applicable Platforms

None (Not Language-Specific, Undetermined)

Demonstrative Examples

Intro: The design of TCP relies on the secrecy of Initial Sequence Numbers (ISNs), as originally covered in CVE-1999-0077 [REF-542]. If ISNs can be guessed (due to predictability, CWE-330) or sniffed (due to lack of encryption during transmission, CWE-312), then an attacker can hijack or spoof connections. Many TCP implementations have had variations of this problem over the years, including CVE-2004-0641, CVE-2002-1463, CVE-2001-0751, CVE-2001-0328, CVE-2001-0288, CVE-2001-0163, CVE-2001-0162, CVE-2000-0916, and CVE-2000-0328.

Notes

Relationship: Note that there is a close relationship between this weakness and CWE-603 (Use of Client-Side Authentication). If developers do not believe that a user can reverse engineer a client, then they are more likely to choose client-side authentication in the belief that it is safe.

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