--- analysis: A detection rule for 'c0000005' crashes is too noisy for production; this hunt filters for specific Rust modules, corroborates with vulnerability status, and pivots to fileless process activity to confirm exploit success. blind_spots: - id: static-library-linking owner: AppSec Team question: Which applications have statically linked a vulnerable version of the Rust standard library? remediation: Implement SBOM generation for all internal Rust projects. requires: Binary static analysis or SBOM tracking risk: A software inventory that only tracks top-level packages will miss vulnerable code embedded inside compiled standalone binaries. stage: vulnerability-inventory - id: no-crash-telemetry owner: Infrastructure Team question: Did the application crash without generating an operating system error log? remediation: Enable application-level crash reporting for critical Rust services. requires: hb_application_error or OS-level crash reporting risk: If an application handles its own segmentation faults or restarts silently, the OS-level crash surface will show no signal. stage: application-crash-violation - id: missing-symbols owner: DevOps question: Does the crash message omit the file paths (str.rs, etc.) because symbols were stripped? remediation: Maintain unstripped binaries in a symbol server for production triage. requires: Unstripped binary symbols risk: The query for specific Rust modules relies on descriptive error messages; if these are stripped, the hunt may fail to identify relevant crashes. stage: memory-safety-exploit-trigger coverage: - stage: vulnerability-inventory status: covered steps: - identify-vulnerable-rust-assets - stage: memory-safety-exploit-trigger status: covered steps: - rust-logic-crashes - stage: application-crash-violation status: covered steps: - rust-logic-crashes - rare-fileless-processes guardrails: claims: no_unsupported evidence: citation_required missing_data: not_benign telemetry: untrusted hunt: applicability: campaign-specific handoff: promote-to-detection justification: The Rust standard library is used in critical internet-facing services; vulnerabilities that allow safe code to trigger memory corruption provide a direct path for initial access through public-facing applications. methodology: model-assisted trigger: intel-report hypothesis: An adversary is exploiting memory-safety vulnerabilities in the Rust standard library (core and std) to trigger undefined behavior and achieve code execution in public-facing applications. labels: - hunt - attack.t1190 - attack.t1499 - impact - initial access name: Rust Standard Library Memory Safety Exploitation parameters: lookback_days: default: '14' description: Days of history to examine for vulnerabilities and runtime activity. type: number rust_modules: default: - str.rs - unix.rs - map_windows.rs - binaryheap.rs description: Rust source files associated with the reported vulnerabilities. from: kind: article observed: '2026-11-09' ref: msrc-blog type: list[string] scope_hosts: default: [] description: Optional list of hostnames to narrow the behavioral analysis after identification. type: list[host] target_cves: default: - CVE-2015-20001 - CVE-2020-36323 description: CVE identifiers for known Rust standard library vulnerabilities. from: kind: article observed: '2026-11-09' ref: msrc-blog type: list[string] provenance: authors: - name: Huntbase hunt generation org: huntbase.io generated: by: huntbase-hunt-generation from: https://www.microsoft.com/en-us/security/blog/2026/11/09/forge-lab-uses-agentic-tools-to-identify-memory-safety-issues-in-rust/ gates: - dry-run - lint model: hb_google/gemini-3-flash-preview rationale: The lead query identifies vulnerable device UIDs; the analyst must translate these to hostnames or use the returned inventory data to populate the 'scope_hosts' parameter for the behavioral branches. references: - name: FORGE Lab uses agentic tools to identify memory safety issues in Rust url: https://www.microsoft.com/en-us/security/blog/2026/11/09/forge-lab-uses-agentic-tools-to-identify-memory-safety-issues-in-rust/ related: - hunt: generic-c0000005-memory-corruption-triage reason: A broader hunt for all memory corruption crashes would catch these triggers but with significantly more noise. relation: out-of-scope-alternative scenario: stages: - name: Identification of Vulnerable Rust Library Versions observables: - Rust core/std version < 1.97.0 - CVE-2015-20001 (BinaryHeap) - CVE-2020-36323 (String joining) - library/core/src/iter/adapters/map_windows.rs slug: vulnerability-inventory tactic: initial-access techniques: - T1190 - name: Triggering Undefined Behavior via Safe APIs observables: - MapWindows::clone - self.buffer - self.start - self.as_array_ref().clone() - BinaryHeap sift_up - BinaryHeap sift_down_range slug: memory-safety-exploit-trigger tactic: initial-access techniques: - T1190 - name: Memory Safety Violation and Process Crash observables: - 'exception_code: c0000005' - str.rs - unix.rs - data.sub - v.begin - v.end - drop_in_place on uninitialized memory - segmentation fault slug: application-crash-violation tactic: impact techniques: - T1499 summary: Microsoft FORGE Lab researchers identified memory-safety vulnerabilities in the Rust standard library (core and std) using agentic AI tools. These flaws, including panic-safety bugs in Iterator::map_windows and race conditions in system interactions, allow safe Rust code to trigger undefined behavior or memory corruption, potentially leading to application crashes in public-facing services. severity: high targets: analyst: name: Tier-2 analyst role: analyst endpoint: category: endpoint name: Endpoint telemetry (hb_ surfaces) telemetry: - endpoint hunter: agent: true name: Hunt agent tlp: clear type: investigation --- # Rust Standard Library Memory Safety Exploitation This hunt identifies applications exposed to memory-safety flaws in Rust's foundational libraries and detects runtime evidence of their exploitation. It starts by identifying assets with known vulnerable Rust packages or CVEs. If vulnerable hosts exist, the hunt investigates application crashes involving memory corruption (c0000005) associated with Rust source modules, as well as fileless process activity which often follows successful memory exploitation. ## identify-vulnerable-rust-assets Identify hosts running Rust packages affected by the target CVEs or using known vulnerable standard library versions. ```sqlite target=endpoint role=scoping params=(target_cves=target_cves) ~~~yaml expected: A list of unique device IDs associated with vulnerable Rust installations. Silence indicates no known vulnerable assets are recorded. reads: - device_uid - cve_uid - affected_package_name - affected_package_version - severity - status silence: not_evidence_of_absence source: hb_vulnerability_finding verified: dry-run verified_at: '2026-11-10' ~~~ SELECT device_uid, cve_uid, affected_package_name, affected_package_version, severity, status FROM hb_vulnerability_finding WHERE (instr(',' || '{{target_cves}}' || ',', ',' || cve_uid || ',') > 0 OR LOWER(affected_package_name) LIKE '%rust%') AND status != 'suppressed' ``` ## evaluate-vuln-lead ```agent target=hunter cite: required context: - identify-vulnerable-rust-assets max_iterations: 3 objective: Assess the prevalence and severity of vulnerable Rust components across the estate and decide if behavioral analysis is required. success_criteria: A recommendation to proceed or end the hunt. tools: - endpoint ``` ## gate-on-vuln if: `identify-vulnerable-rust-assets.rows > 0` then: → corroborate-exploitation else: → close-out ## corroborate-exploitation parallel: - → rust-logic-crashes - → rare-fileless-processes join: → final-triage ## rust-logic-crashes Identify application crashes with exception c0000005 that reference specific Rust library modules or panic signatures. ```sqlite target=endpoint role=detection-candidate params=(lookback_days=lookback_days, rust_modules=rust_modules, scope_hosts=scope_hosts) ~~~yaml expected: Crash events where the error message includes Rust library internal files or runtime panics. Silence means no such crashes were recorded. reads: - device_hostname - app_name - exception_code - message - time silence: not_evidence_of_absence source: hb_application_error verified: dry-run verified_at: '2026-11-10' ~~~ SELECT device_hostname, app_name, exception_code, message, time FROM hb_application_error WHERE exception_code = 'c0000005' AND (LOWER(message) LIKE '%panicked at%' OR LOWER(message) LIKE '%core::%' OR LOWER(message) LIKE '%std::%' OR instr(',' || '{{rust_modules}}' || ',', ',' || LOWER(message) || ',') > 0) AND ('{{scope_hosts}}' = '' OR instr(',' || '{{scope_hosts}}' || ',', ',' || device_hostname || ',') > 0) AND time >= datetime('now', '-{{lookback_days}} days') ``` ## rare-fileless-processes Identify processes running with no image on disk, which suggests code injection after a memory-safety exploit. ```sqlite target=endpoint role=baseline params=(lookback_days=lookback_days, scope_hosts=scope_hosts) ~~~yaml baseline: compare: first_seen window: '{{lookback_days}}d' expected: Injected or fileless processes that are unique to a few hosts. Silence means no fileless activity was found. prevalence: by: device_hostname key: - process_name rare_below: 3 reads: - device_hostname - process_path - process_name - process_cmd_line - on_disk - time silence: not_evidence_of_absence source: hb_process_activity verified: dry-run verified_at: '2026-11-10' ~~~ SELECT device_hostname, process_path, process_name, process_cmd_line, COUNT(DISTINCT device_hostname) AS host_count, MIN(time) AS first_seen FROM hb_process_activity WHERE on_disk = 0 AND ('{{scope_hosts}}' = '' OR instr(',' || '{{scope_hosts}}' || ',', ',' || device_hostname || ',') > 0) AND time >= datetime('now', '-{{lookback_days}} days') GROUP BY process_name HAVING host_count <= 3 ``` ## final-triage ```agent target=hunter cite: required context: - evaluate-vuln-lead - rust-logic-crashes - rare-fileless-processes max_iterations: 3 objective: Determine if any single host shows a combination of a Rust-related crash and a rare fileless process, especially if that host was previously flagged as vulnerable. success_criteria: A per-host verdict of malicious, suspicious, or benign, citing specific rows. tools: - endpoint ``` ## final-decision if~: "the final-triage verdict is malicious for at least one host" (confidence: high, judge=hunter) then: → isolate-target indeterminate: → analyst-forensic-review unavailable: → analyst-forensic-review (blind_spot: no-crash-telemetry) else: → close-out ## isolate-target ```action target=endpoint ~~~yaml approval: required ~~~ Isolate the host from the network and collect a full memory dump for analysis. ``` → analyst-forensic-review ## analyst-forensic-review ```manual target=analyst Review the crash dump for the 'c0000005' violation. Look for signs of heap spraying or shellcode. Examine the stack trace to see if the exception occurred during a BinaryHeap operation or a String join as mentioned in the CVEs. ``` → close-out ## close-out ```manual target=analyst Document the findings and update the software inventory to ensure all identified vulnerable Rust binaries are patched. If no activity was found, record the negative result as evidence of security posture. ``` → end