CISA has issued a crucial warning relating to a path traversal vulnerability within the Ruby on Rails framework that poses vital dangers to net functions worldwide.
The vulnerability, cataloged as CVE-2019-5418, impacts the Motion View part of Rails and permits attackers to use specifically crafted settle for headers together with render file: calls to entry arbitrary recordsdata on course servers.
This safety flaw was added to CISA’s Identified Exploited Vulnerabilities (KEV) catalog on July 7, 2025, with organizations given till July 28, 2025, to implement crucial mitigations or discontinue use of affected merchandise.
Key Takeaways1. CVE-2019-5418 in Ruby on Rails permits attackers to entry arbitrary server recordsdata by way of exploited Settle for headers and render file calls.2. Permits unauthorized entry to delicate system recordsdata, configurations, and credentials by way of malicious HTTP Settle for headers with listing traversal sequences.3. Added to CISA’s KEV catalog July 7, 2025, with a compulsory mitigation deadline of July 28, 2025, on account of lively exploitation.4. Replace to patched Rails variations (4.2.5.1, 5.1.6.2+), implement enter validation, and comply with BOD 22-01 steerage or discontinue use.
Path Traversal Vulnerability
The CVE-2019-5418 vulnerability represents a basic path traversal assault vector that particularly targets the Rails framework’s Motion View part.
This vulnerability falls below the Widespread Weak point Enumeration class CWE-22, which encompasses path traversal weaknesses that permit attackers to entry recordsdata and directories saved outdoors the meant listing construction.
The vulnerability happens when functions use the render file: technique together with user-controlled enter, notably by way of manipulated HTTP Settle for headers.
The technical basis of this exploit lies in how Rails processes file rendering requests.
When an utility calls render file: with inadequate enter validation, attackers can craft malicious Settle for headers containing listing traversal sequences comparable to ../ to navigate outdoors the appliance’s meant file scope.
This weak point permits unauthorized entry to delicate system recordsdata, configuration recordsdata, and doubtlessly database credentials saved on the server filesystem.
The exploitation mechanism includes setting up specifically crafted HTTP requests with manipulated Settle for headers that bypass Rails’ meant safety controls. Attackers sometimes goal functions that implement code patterns just like:
The assault payload leverages path traversal sequences embedded inside Settle for headers, comparable to:
This method permits attackers to traverse the listing construction and entry crucial system recordsdata together with /and many others/passwd, utility configuration recordsdata, and doubtlessly supply code containing delicate info.
The vulnerability’s severity is amplified as a result of it could result in arbitrary file disclosure, exposing confidential information that might facilitate additional assaults or system compromise.
Danger FactorsDetailsAffected ProductsRuby on Rails framework (Motion View part)- Variations previous to Rails 4.2.5.1- Variations previous to Rails 5.1.6.2Impact– Arbitrary file disclosure- Unauthorized entry to delicate server filesExploit Conditions– Software makes use of render file: method- Consumer-controlled enter in file rendering calls- Capacity to craft malicious HTTP Settle for headers- No correct enter validation or path sanitizationCVSS 3.1 Score7.5 (Excessive)
Mitigation Methods
CISA mandates that federal businesses and organizations apply vendor-provided mitigations instantly, following relevant BOD 22-01 steerage for cloud providers.
The first mitigation includes updating Rails to patched variations: Rails 4.2.5.1, Rails 5.1.6.2, or later variations that tackle this vulnerability.
Organizations ought to implement strict enter validation for any file rendering operations and keep away from utilizing render file: with user-controlled parameters.
Extra protecting measures embrace implementing correct entry controls, conducting thorough code evaluations to determine susceptible patterns, and deploying Net Software Firewalls (WAF) configured to detect and block path traversal makes an attempt.
Organizations should additionally be certain that functions comply with the precept of least privilege, proscribing file system entry to solely crucial directories and implementing complete logging to detect potential exploitation makes an attempt.
The July 28, 2025, deadline emphasizes the urgency of addressing this vulnerability, notably given its inclusion in CISA’s KEV catalog, which signifies lively exploitation in real-world assaults.
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