CVE-2017-20202
Published: 08 October 2025
Summary
CVE-2017-20202 is a critical-severity Embedded Malicious Code (CWE-506) vulnerability in Proofpoint (inferred from references). Its CVSS base score is 9.3 (Critical).
Operationally, ranked at the 29.9th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-33277
Vulnerability details
Web Developer for Chrome v0.4.9 contained malicious code that generated a domain via a DGA and fetched a remote script. The fetched script conditionally loaded follow-on modules that performed extensive ad substitution and malvertising, displayed fake “repair” alerts that redirected…
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users to affiliate programs, and attempted to harvest credentials when users logged in. Injected components enumerate common banner sizes for substitution, replace third-party ad calls, and redirect victim traffic to affiliate landing pages. Potential impacts include user-level code execution in the browser context, large-scale ad fraud and traffic hijacking, credential theft, and exposure to additional payloads delivered by the actor. The compromise was reported on by the maintainer of Web Developer for Chrome on August 2, 2017 and remediated in v0.5.0.
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Restricting software to licensed versions and controlling P2P prevents introduction of software containing embedded malicious code from unauthorized sources.
The control prevents users from installing software that contains embedded malicious code.
Regular inventory reviews and updates make it harder to conceal or exploit embedded malicious code by requiring all components to be documented and accounted for.
Reverting to a known state removes any malicious code embedded by an attacker.
The approval and review process for maintenance tools can prevent introduction or continued use of tools containing embedded malicious code.
Supply chain strategy requires vetting and controls during acquisition to prevent or detect insertion of malicious code by vendors or integrators.
Background screening for development or deployment roles makes intentional insertion of malicious code by insiders materially harder to accomplish.
The capability explicitly searches for embedded malicious code and backdoors as indicators of compromise.