CWE-1244: Internal Asset Exposed to Unsafe Debug Access Level or State

Extended Description

Debug authorization can have multiple levels of access, defined such that different system internal assets are accessible based on the current authorized debug level. Other than debugger authentication (e.g., using passwords or challenges), the authorization can also be based on the system state or boot stage. For example, full system debug access might only be allowed early in boot after a system reset to ensure that previous session data is not accessible to the authenticated debugger.

Code Examples & CVEs

Demonstrative Examples

The JTAG interface is used to perform debugging and provide CPU core access for developers. JTAG-access protection is implemented as part of the JTAG_SHIELD bit in the hw_digctl_ctrl register. This register has no default value at power up and is set only after the system boots from ROM and control is transferred to the user software.

This means that since the end user has access to JTAG at system reset and during ROM code execution before control is transferred to user software, a JTAG user can modify the boot flow and subsequently disclose all CPU information, including data-encryption keys.

BadOther

1 bit                                     0x0 = JTAG debugger is enabled (default)                                                                                                       JTAG_SHIELD                                     0x1 = JTAG debugger is disabled

The example code below is taken from the CVA6 processor core of the HACK@DAC'21 buggy OpenPiton SoC. Debug access allows users to access internal hardware registers that are otherwise not exposed for user access or restricted access through access control protocols. Hence, requests to enter debug mode are checked and authorized only if the processor has sufficient privileges. In addition, debug accesses are also locked behind password checkers. Thus, the processor enters debug mode only when the privilege level requirement is met, and the correct debug password is provided.

The following code [REF-1377] illustrates an instance of a vulnerable implementation of debug mode. The core correctly checks if the debug requests have sufficient privileges and enables the debug_mode_d and debug_mode_q signals. It also correctly checks for debug password and enables umode_i signal.

BadVerilog

module csr_regfile #(                     ...                                                  // check that we actually want to enter debug depending on the privilege level we are currently in                         unique case (priv_lvl_o)                                                          riscv::PRIV_LVL_M: begin                                                                  debug_mode_d = dcsr_q.ebreakm;                                                                                                            ...                                                                                   riscv::PRIV_LVL_U: begin                                                                  debug_mode_d = dcsr_q.ebreaku;                                                                                                            ...                                                  assign priv_lvl_o = (debug_mode_q || umode_i) ?  riscv::PRIV_LVL_M : priv_lvl_q;                                              ...                                                  debug_mode_q  <= debug_mode_d;                                              ...

GoodVerilog

module csr_regfile #(                     ...                                                  // check that we actually want to enter debug depending on the privilege level we are currently in                         unique case (priv_lvl_o)                                                          riscv::PRIV_LVL_M: begin                                                                  debug_mode_d = dcsr_q.ebreakm;                                                                                                            ...                                                                                   riscv::PRIV_LVL_U: begin                                                                  debug_mode_d = dcsr_q.ebreaku;                                                                                                            ...                                                  assign priv_lvl_o = (debug_mode_q && umode_i) ? riscv::PRIV_LVL_M : priv_lvl_q;                                              ...                                                  debug_mode_q  <= debug_mode_d;                                              ...

Observed CVE Examples (1)

CVE-2019-18827

After ROM code execution, JTAG access is disabled. But before the ROM code is executed, JTAG access is possible, allowing a user full system access. This allows a user to modify the boot flow and successfully bypass the secure-boot process.

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Source-backed guidance

Additional facts reviewed against primary or authoritative security sources.

Verify controls for CWE-1244 with SSDF evidence

Use NIST SSDF verification and vulnerability-response practices to detect CWE-1244, Internal Asset Exposed to Unsafe Debug Access Level or State, throughout the product lifecycle. Derive review questions, static or dynamic checks, and negative tests from the CWE's causal behavior; define the components and lifecycle stages each check covers; and retain findings with enough evidence to distinguish the root cause from symptoms and impacts. Track escapes and false negatives, then improve the verification plan after every confirmed occurrence.

NIST SP 800-218 Secure Software Development Framework — National Institute of Standards and Technology

Address Internal Asset Exposed to Unsafe Debug Access Level or State during Architecture and Design

MITRE associates mitigation with Architecture and Design, and Implementation; documented detection approaches include Manual Analysis; recorded impacts include Read Memory, Modify Memory, Gain Privileges or Assume Identity, and Bypass Protection Mechanism. Use these source-defined anchors to turn CWE-1244 into implementation, review, and verification checks for the affected component.

CWE-1244: Internal Asset Exposed to Unsafe Debug Access Level or State — MITRE CWE

Triage CWE-1244 against known exploitation evidence

Use CISA's Known Exploited Vulnerabilities catalog to test whether a vulnerability mapped to CWE-1244, Internal Asset Exposed to Unsafe Debug Access Level or State, has evidence of exploitation in the wild. Confirm the CVE-to-CWE root-cause mapping independently before attaching the example, then capture the affected product, required action, and remediation deadline. A missing KEV match is not evidence that the weakness is unexploited, and a KEV entry must not be generalized to every occurrence of this CWE.

Known Exploited Vulnerabilities Catalog — Cybersecurity and Infrastructure Security Agency

Apply precise root-cause mapping to CWE-1244

Apply MITRE's full root-cause mapping guidance when using CWE-1244, Internal Asset Exposed to Unsafe Debug Access Level or State. Separate weakness language from attacker prerequisites and technical impact, check the entry's abstraction and vulnerability-mapping notes, and prefer the most specific Base or Variant supported by the evidence. Record the rejected alternatives and require an independent review before the mapping is used for remediation trends or program metrics.

CVE to CWE Root Cause Mapping Guidance — MITRE CWE

Validate CWE-1244 with root-cause mapping checks

Apply MITRE's root-cause mapping quick tips to CWE-1244, Internal Asset Exposed to Unsafe Debug Access Level or State. Confirm the finding describes the causal weakness rather than an impact or attack pattern, compare the abstraction and mapping notes with plausible alternatives, and have a second reviewer challenge the selection. Preserve the evidence and reasoning so recurring defects can be measured against one consistent identifier.

CVE to CWE Root Cause Mapping Quick Tips — MITRE CWE

Frequently Asked Questions

What is CWE-1244: Internal Asset Exposed to Unsafe Debug Access Level or State?+

CWE-1244: Internal Asset Exposed to Unsafe Debug Access Level or State is a Common Weakness Enumeration (CWE) entry maintained by MITRE. The product uses physical debug or test interfaces with support for multiple access levels, but it assigns the wrong debug access level to an internal asset, providing unintended access to the asset from untrusted debug agents. Debug authorization can have multiple levels of access, defined such that different system internal assets are accessible based on the current authorized debug level. Other than debugger authentication (e.g., using passwords or challenges), the authorization can also be based on the system state or boot stage. For example, full system debug access might only be allowed early in boot after a system reset to ensure that previous session data is not accessible to the authenticated debugger.

What are the security consequences of Internal Asset Exposed to Unsafe Debug Access Level or State?+

If exploited, CWE-1244 (Internal Asset Exposed to Unsafe Debug Access Level or State) it can compromise Confidentiality, Integrity, Authorization and Access Control, leading to outcomes such as Read Memory, Modify Memory, Gain Privileges or Assume Identity and Bypass Protection Mechanism.

How do you prevent or mitigate Internal Asset Exposed to Unsafe Debug Access Level or State?+

Recommended mitigations for CWE-1244 include: For security-sensitive assets accessible over debug/test interfaces, only allow trusted agents. Apply blinding [REF-1219] or masking techniques in strategic areas. Add shielding or tamper-resistant protections to the device, which increases the difficulty and cost for accessing debug/test interfaces.

How is Internal Asset Exposed to Unsafe Debug Access Level or State detected?+

CWE-1244 can be detected using Manual Analysis. Combining automated tooling with manual review typically yields the best coverage.

Which programming languages are affected by Internal Asset Exposed to Unsafe Debug Access Level or State?+

CWE-1244 commonly affects Not Language-Specific. Note that weaknesses are often language-agnostic patterns, so secure coding practices apply broadly.

What are real-world examples of Internal Asset Exposed to Unsafe Debug Access Level or State?+

MITRE documents real CVEs mapped to CWE-1244, including CVE-2019-18827. You can look up the full details of each CVE, including CVSS scores and remediation guidance, on our CVE Lookup tool.

What is the difference between a CWE and a CVE?+

A CWE (Common Weakness Enumeration) like CWE-1244 describes a category of software weakness — the underlying flaw type. A CVE (Common Vulnerabilities and Exposures) identifies a specific, real-world vulnerability in a particular product. In short, a CWE is the kind of mistake, and a CVE is an instance of that mistake being found in software.

CWE-1244: Internal Asset Exposed to Unsafe Debug Access Level or State

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Code Examples & CVEs

Demonstrative Examples

Observed CVE Examples (1)

CWE Relationships

Parent Weaknesses

Source-backed guidance

Verify controls for CWE-1244 with SSDF evidence

Address Internal Asset Exposed to Unsafe Debug Access Level or State during Architecture and Design

Triage CWE-1244 against known exploitation evidence

Apply precise root-cause mapping to CWE-1244

Validate CWE-1244 with root-cause mapping checks

Frequently Asked Questions

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