CVE-2014-0497

What Is Adobe Flash Player?

Adobe Flash Player was a browser plugin that enabled interactive multimedia content, animations, and video playback across the web. At peak adoption (2010–2014), Flash was installed on over 90% of internet-connected desktop computers and was the dominant platform for browser-based games, video streaming, and interactive advertising. This near-universal installation footprint, combined with Flash's rich scripting capabilities (ActionScript), made it the most-targeted browser plugin in the history of exploitation — responsible for a disproportionate share of all browser-based zero-day attacks between 2005 and 2020. Flash reached end-of-life on December 31, 2020.

Overview

CVE-2014-0497 is a critical integer underflow vulnerability in Adobe Flash Player's ActionScript bytecode interpreter or JIT compilation engine. A specially crafted SWF file can trigger the underflow — where a calculation produces a value that wraps below zero — causing a heap buffer overwrite. The resulting memory corruption enables arbitrary code execution with no user interaction beyond visiting a compromised web page. The vulnerability was exploited as a zero-day (before Adobe released a patch), triggering an emergency out-of-band security bulletin (APSB14-04) on February 5, 2014.

Affected Versions

Technical Details

Root Cause: Integer Underflow in ActionScript Processing

An integer underflow occurs when a calculation produces a result below the minimum value a data type can represent, causing it to wrap around to a very large positive number. In Flash Player's case, this affects the ActionScript interpreter or JIT compiler when processing a malformed SWF file.

The attack flow:

1. Attacker serves a crafted SWF file embedded in a web page (or as a standalone link)
2. When loaded by Flash Player, the malformed ActionScript triggers an integer calculation that underflows
3. The underflowed value is used as a size or offset parameter in a heap memory operation
4. Flash writes attacker-controlled data to a region of heap memory much larger or in a different location than intended
5. The corrupted heap state leads to control-flow hijacking and arbitrary code execution

Because the vulnerability requires no user authentication and only requires the victim to visit a web page containing the malicious Flash content, it carries a CVSS 9.8 CRITICAL rating — the highest possible for this attack type.

Attack Characteristics

Discovery

Security researchers (including from Kaspersky Lab) observed exploitation of this zero-day in late January 2014 and reported it to Adobe. Adobe prepared and released an emergency out-of-band patch (APSB14-04) on February 5, 2014 — bypassing their normal quarterly patch cadence due to the severity and confirmed in-the-wild exploitation.

Exploitation Context

• Zero-day: Exploited in targeted attacks for approximately one week before Adobe released the emergency patch
• Threat actor attribution: Attributed by some security researchers to a Chinese APT group conducting targeted espionage operations, primarily against organizations in Japan and the broader Asia-Pacific region
• Delivery mechanism: Malicious or compromised websites serving SWF files; also delivered via malicious Office documents with embedded Flash objects
• Impact: Victims could be silently compromised (code execution with no visible indication) by simply visiting a web page in a browser with Flash enabled
• CISA KEV (2024): Added to KEV catalog in September 2024, reflecting that even decade-old Flash vulnerabilities continue to be exploited against systems that have not removed Flash

Remediation

1. Remove Adobe Flash Player. Flash Player reached end-of-life on December 31, 2020. There are no further security patches. The only complete mitigation is uninstallation. Adobe provides a Flash Player uninstaller at helpx.adobe.com.

2. Verify Flash removal: Check browser plugins (browser settings → plugins/extensions) and Windows Programs & Features for "Adobe Flash Player." Flash should not be present on any modern system.

3. Block Flash content at the network layer if Flash cannot be immediately removed from legacy systems: web proxy rules blocking .swf file downloads.

4. Audit legacy applications that may have embedded Flash requirements — replace with HTML5/JavaScript equivalents.

5. For historical reference: the original fix was to update Flash Player to 12.0.0.44 or 11.7.700.261+ per APSB14-04.