git:20260629.95337a2 to git:20260629.9f4a1a5

1 added, 1 removed. Audit A to A.

---

name: browser-exploitation

- description: Client-side browser exploitation — V8/JSC engine bug classes, JIT type confusion to in-renderer R/W, V8 heap-sandbox escape, renderer-to-browser sandbox escape (Mojo IPC, GPU/Dawn/ANGLE), Electron/webview IPC abuse, and full 1-click client-side RCE chain assembly

+ description: Use when building a client-side browser exploit — V8/JSC JIT type confusion to renderer R/W, V8 heap-sandbox escape, renderer-to-browser sandbox escape (Mojo IPC, GPU/Dawn/ANGLE), Electron/webview IPC abuse, 1-click RCE chains

metadata:

type: offensive

phase: exploitation

tools: d8, gdb-gef, pwndbg, lldb, WinDbg, IDA, Frida, jsvu, asar, electronegativity, Wireshark, mojo-tools

mitre: [T1203, T1189, T1059.007, T1068, T1055, T1574]

kill_chain:

phase: [weaponize, deliver, exploit]

step: [2, 3, 4]

attck_tactics: [TA0042, TA0001, TA0002, TA0004]

attck_techniques: [T1203, T1189, T1059.007, T1068, T1055.012, T1574.002]

depends_on: [recon-osint, vulnerability-analysis, exploit-development, reverse-engineering]

feeds_into: [initial-access, edr-evasion, shellcode-dev, privesc-windows, privesc-linux, red-team-ops]

inputs: [target_browser_versions, vulnerability_list, crash_corpus, electron_app_build, attack_surface_map]

outputs: [renderer_rw_primitive, sandbox_escape_poc, clientside_rce_chain, exploit_poc, finding_record]

references:

- references/v8-jit-typeconfusion.md

- references/v8-sandbox-escape.md

- references/renderer-to-browser-escape.md

- references/electron-webview-rce.md

- references/clientside-rce-chains.md

scripts:

- scripts/v8_typer.js

- scripts/sandbox_escape.js

- scripts/mojo_fuzz_harness.py

- scripts/electron_audit.py

- scripts/chain_server.py

- scripts/d8_debug.sh

---

# Browser & Client-Side Exploitation

Turn a single client-side bug into full host compromise. The modern browser is a chain target: a JS-engine bug yields an in-renderer arbitrary read/write, the V8 heap sandbox must be escaped to get a native R/W, then a second logic/memory bug in a privileged process (browser broker, GPU) escapes the OS sandbox. Electron and embedded webviews collapse several of these steps. Every cluster pairs the offensive primitive with renderer-crash/IPC telemetry, Sigma/EDR detection, and cleanup OPSEC.

## When to Activate

- A V8/JavaScriptCore bug (type confusion, OOB, UAF, JIT mis-speculation) must become `addrof`/`fakeobj` and an in-renderer arbitrary R/W.

- An in-renderer R/W exists but is trapped inside the **V8 heap sandbox** (pointer compression) and needs a trusted-pointer / Wasm-object escape to native memory.

- A renderer is fully compromised and you need to escape the **OS sandbox** via Mojo IPC handle/logic bugs or the GPU process (Dawn/WebGPU, ANGLE).

- Auditing or exploiting an **Electron / CEF / WebView2** app: `contextIsolation`/`nodeIntegration`/`sandbox` misconfig, preload-bridge & IPC abuse, ASAR/fuse/snapshot tampering.

- Assembling a **1-click drive-by RCE chain** (renderer → sandbox escape → host) for an authorized red-team delivery, or doing cross-engine (Safari/JSC) work.

- Patch-diffing a Chrome/V8/WebKit security release to build an n-day client-side exploit.

## Technique Map

|-----------|--------|-----|-----------|--------|

## Quick Start

```bash

# 0. Pin the exact target build (Chrome/Edge/Electron all carry a V8 version)

# chrome://version | edge://version | electron --version

jsvu --engines=v8 # local d8 of matching version

./scripts/d8_debug.sh ./d8 ./poc.js # d8 w/ exploit-friendly flags

# 1. Engine bug -> in-renderer R/W (see references/v8-jit-typeconfusion.md)

d8 --allow-natives-syntax --shell ./scripts/v8_typer.js

# yields addrof(), fakeobj(), read64()/write64() inside the V8 heap cage

# 2. Escape the V8 heap sandbox -> native R/W (references/v8-sandbox-escape.md)

d8 --no-sandbox-testing-mode ./scripts/sandbox_escape.js # local test;

# on a real build: abuse trusted Wasm object raw pointer -> overwrite RWX Wasm code

# 3. Escape the OS sandbox: Mojo broker logic bug OR GPU-process memory bug

python3 scripts/mojo_fuzz_harness.py --interface FileSystemAccess --iters 100000

# 4. Electron / webview target: audit + weaponize

python3 scripts/electron_audit.py /path/to/app.asar # finds nodeIntegration/IPC/fuse gaps

# craft IPC/preload payload from the report; package XSS->RCE

# 5. Stage the full 1-click chain and serve it

python3 scripts/chain_server.py --stage1 renderer.js --stage2 escape.js --lhost 10.0.0.5 --lport 8080

```

## OPSEC & Detection (summary)

|-----------|---------------|-----------------------|------------|

| JIT type confusion | Renderer crash dumps (`chrome_crashpad`, `crashpad_handler`), GPU/renderer restarts, `*-crash` in `~/AppData/Local/.../Crashpad` | Sigma: spike in renderer crash reports; EDR on `crashpad_handler` bursts | Spray/clean up corrupted arrays; bail without crashing on failed type-check; do not leave `%DebugPrint` calls |

| V8 sandbox escape | Native R/W faults if math is off; abnormal RWX Wasm pages | EDR: RWX region churn inside `chrome.exe`/renderer; ETW `VirtualProtect` to RWX | Keep corruption inside the cage until the last step; reuse existing RWX Wasm code page rather than allocating new |

| Mojo broker escape | Browser process spawning `cmd.exe`/`powershell.exe`/`rundll32.exe`; unexpected file writes by broker | Sigma: `chrome.exe`/`msedge.exe` parent -> shell child; EDR child-process rule; Mojo message audit | Live off the broker's own capabilities (file write, process launch); avoid spawning a console child — inject instead |

| GPU-process bug | GPU process crashes (`--type=gpu`), Dawn/ANGLE asserts, `DXGI`/`Metal` faults | EDR on GPU-process child anomalies; WebGPU enabled via policy = surface | Test against the right GPU backend (D3D11/Metal/Vulkan); fail closed without crashing the GPU process |

| Electron IPC/preload RCE | `app.asar` mtime change, `node` child of Electron app, `child_process.exec` | Sigma: Electron app spawning shells; FIM on `app.asar`/snapshot blobs | Prefer in-process JS exec (require gadget) over `child_process`; restore `app.asar` mtime after fuse/snapshot tamper |

| Drive-by chain delivery | Suspicious `text/html` with large encoded JS, WebSocket/long-poll to attacker host, UA-gated content | Proxy/Sigma on long base64/`%u` blobs in HTML; JA3/JA4 of staging host | UA/feature gate so only the exact target build receives stage-2; single-use, expiring URLs |

## Deep Dives

- references/v8-jit-typeconfusion.md — V8 object model, Map/element-kinds, TurboFan/Maglev/Turboshaft speculation bugs; CVE-2024-4947/5274, CVE-2025-2135/5419/10585 patterns. Build `addrof`/`fakeobj` and an in-cage arbitrary R/W via a fake TypedArray. Backed by `v8_typer.js`, `d8_debug.sh`.

- references/v8-sandbox-escape.md — The V8 heap sandbox (pointer compression, external-pointer & trusted-pointer tables); escaping via raw pointers in Wasm objects (WasmIndirectFunctionTable / Liftoff), Trusted Pointer Table abuse, and pivot to RWX Wasm code. Backed by `sandbox_escape.js`.

- references/renderer-to-browser-escape.md — Escaping the OS sandbox: Mojo IPC handle-confusion logic bugs (CVE-2025-2783 ForumTroll, CVE-2025-4609 ipcz), GPU-process memory bugs (Dawn/WebGPU, ANGLE CVE-2025-6558), fuzzing Mojo interfaces. Backed by `mojo_fuzz_harness.py`.

- references/electron-webview-rce.md — Electron/CEF/WebView2 model; `nodeIntegration`/`contextIsolation`/`sandbox` matrix, preload-bridge & IPC abuse, deprecated `webviewTag`, ASAR integrity bypass (CVE-2025-55305) and V8 snapshot/fuse tampering, XSS->RCE. Backed by `electron_audit.py`.

- references/clientside-rce-chains.md — Stitching primitives into a reliable 1-click chain; staged delivery, UA/feature gating, reliability hardening, cross-engine (JSC/WebKit CVE-2025-43529) primitive porting, patch-diffing for n-days. Backed by `chain_server.py`.