CVE-2014-2817

What Is Internet Explorer Protected Mode?

Internet Explorer's Protected Mode (introduced in IE 7 for Windows Vista) runs the IE content process at a low-integrity level, restricting its ability to write to the filesystem, registry, and other system resources. This "sandboxing" mechanism is designed to contain exploitation: even if an attacker achieves code execution inside the IE rendering process, they are confined to the low-integrity sandbox and cannot perform most harmful actions without a "privilege escalation" or "elevation" step that breaks out of the sandbox.

Privilege escalation vulnerabilities in Internet Explorer — like CVE-2014-2817 — are therefore second-stage exploits that complete the sandbox escape, transforming a sandboxed code execution into full OS-level access at the user's privilege level.

Overview

CVE-2014-2817 is a privilege escalation vulnerability in Internet Explorer that allows a sandboxed or low-privilege IE process to elevate to higher OS privileges via a crafted web page. The vulnerability enables an attacker who has already achieved code execution within IE's Protected Mode sandbox to escape it — turning a contained exploit into a full user-level compromise. Patched in MS14-051 (August 12, 2014).

Affected Versions

Fixed in MS14-051 (August 12, 2014 — Patch Tuesday).

Technical Details

Root Cause: Privilege Enforcement Bypass in IE

CVE-2014-2817 involves a flaw in how Internet Explorer enforces zone security or integrity-level boundaries. The vulnerability allows an object or operation accessible from a low-integrity (sandboxed) IE process to perform an action that should require higher integrity — effectively allowing code running in Protected Mode to trigger behavior at medium or high integrity.

The specific mechanism involves improper validation in IE's cross-zone or cross-process communication path. By crafting web page content that triggers this flawed code path, an attacker can cause IE to perform a privileged action (e.g., write to a protected location, execute code at a higher integrity level) on behalf of the attacker's low-integrity content.

Role in Exploit Chains

Like CVE-2014-4113 (Win32k LPE), CVE-2014-2817 is most valuable as the second stage of a two-stage exploit chain:

• Stage 1: An IE memory corruption vulnerability (use-after-free, heap overflow, etc.) achieves code execution inside IE's Protected Mode sandbox
• Stage 2: CVE-2014-2817 escapes the sandbox, giving the attacker full access at the OS user-privilege level

This chain pattern — RCE inside sandbox + privilege escalation out of sandbox — is the standard model for complete browser-based attacks.

Attack Characteristics

Discovery

Reported to Microsoft and patched in the August 2014 Patch Tuesday bulletin MS14-051, which addressed 26 total vulnerabilities in Internet Explorer.

Exploitation Context

• Exploit chain component: Used in advanced browser exploit chains to escape IE's Protected Mode sandbox after initial code execution
• APT toolkits: Privilege escalation bugs of this class are a standard component of nation-state browser exploit chains; they enable full machine compromise via a single browser drive-by
• Exploit kit adoption: IE privilege escalation vulnerabilities are regularly incorporated into exploit kits as part of multi-stage payloads targeting fully-patched systems (where the attacker needs both RCE and LPE)
• CISA KEV (2022): Added May 2022, confirming continued exploitation of this vulnerability in attacks against unpatched IE deployments

Remediation

1. Apply MS14-051 (August 2014 cumulative IE update).

2. Migrate off Internet Explorer. Microsoft retired IE on June 15, 2022. No further security updates are available. Any active IE use permanently exposes users to this and many other unfixed vulnerabilities.

3. Enable Enhanced Protected Mode (EPM) in IE 10/11 — EPM uses a more restrictive sandbox (AppContainer) that provides stronger isolation than standard Protected Mode, raising the bar for sandbox escapes.

4. Use Microsoft Edge (Chromium-based) as the replacement for IE — it has a modern sandbox architecture with AppContainer isolation.

5. Block IE execution via AppLocker or Windows Defender Application Control if complete removal is not possible in the near term.