CWE-1342: Information Exposure through Microarchitectural… | Glexia
CWE-1342 (Information Exposure through Microarchitectural State after Transient Execution) weakness overview with consequences, detection methods, mitigations,…
Glexia's Take · Automated analysis
CWE-1342: Information Exposure through Microarchitectural State after Transient Execution
Information Exposure through Microarchitectural State after Transient Execution represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Executive Impact
- Confidentiality Integrity: Modify Memory Read Memory Execute Unauthorized Code or Commands
Developer Pattern
CWE-1342 is the kind of defect developers can usually prevent with explicit validation, safer framework defaults, and tests that exercise hostile input or unsafe state transitions.
Automation confidence
high confidence from CWE-1342, 4.20.
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Official CWE Definition
CWE-1342: Information Exposure through Microarchitectural State after Transient Execution
The processor does not properly clear microarchitectural state after incorrect microcode assists or speculative execution, resulting in transient execution.
In many processor architectures an exception, mis-speculation, or microcode assist results in a flush operation to clear results that are no longer required. This action prevents these results from influencing architectural state that is intended to be visible from software. However, traces of this transient execution may remain in microarchitectural buffers, resulting in a change in microarchitectural state that can expose sensitive information to an attacker using side-channel analysis. For example, Load Value Injection (LVI) [REF-1202] can exploit direct injection of erroneous values into intermediate load and store buffers. Several conditions may need to be fulfilled for a successful attack: incorrect transient execution that results in remanence of sensitive information; attacker has the ability to provoke microarchitectural exceptions; operations and structures in victim code that can be exploited must be identified.
Developer And Remediation Guidance
How teams prevent and detect this weakness
Causes
- Faulting loads in a victim domain may trigger incorrect transient forwarding, which leaves secret-dependent traces in the microarchitectural state. Consider this example from [REF-1203]. Consider the code gadget: A processor with this weakness will store the value of untrusted_arg (which may be provided by an attacker) to the stack, which is trusted memory. Additionally, this store operation will save this value in some microarchitectural buffer, e.g. the store queue. In this code gadget, trusted_ptr is dereferenced while the attacker forces a page fault. The faulting load causes the processor to mis-speculate by forwarding untrusted_arg as the (speculative) load result. The processor then uses untrusted_arg for the pointer dereference. After the fault has been handled and the load has been re-issued with the correct argument, secret-dependent information stored at the address of trusted_ptr remains in microarchitectural state and can be extracted by an attacker using a code gadget.
Remediation
- Architecture and Design Requirements: Hardware ensures that no illegal data flows from faulting micro-ops exists at the microarchitectural level.
- Build and Compilation: Include instructions that explicitly remove traces of unneeded computations from software interactions with microarchitectural elements e.g. lfence, sfence, mfence, clflush.
Detection
- Code review
- SAST
- DAST
- Focused regression tests
Mappings
Related CVEs, CWEs, and ATT&CK context
Related CWEs
ATT&CK Relevance
ATT&CK relevance is shown only when reviewed or responsibly inferred.