CVE-2020-28275 in cache-base
Summary
by MITRE • 12/30/2020
Prototype pollution vulnerability in 'cache-base' versions 0.7.0 through 4.0.0 allows attacker to cause a denial of service and may lead to remote code execution.
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Analysis
by VulDB Data Team • 12/30/2020
The cache-base library vulnerability represents a critical prototype pollution flaw that affects versions ranging from 0.7.0 through 4.0.0, creating significant security implications for applications that rely on this dependency. This vulnerability stems from insufficient input validation during object property assignment operations, allowing attackers to manipulate the prototype of objects within the JavaScript runtime environment. The issue manifests when the library processes user-controlled data without proper sanitization, enabling malicious actors to inject properties into the Object.prototype chain.
The technical exploitation of this vulnerability occurs through careful manipulation of object merging or assignment operations where the cache-base library fails to distinguish between legitimate and malicious property names. When attackers supply crafted input containing prototype-polluting keys such as _proto_, constructor, or prototype, these properties get assigned to objects within the application's memory space. This contamination can propagate throughout the application's object hierarchy, affecting all subsequent object operations that rely on the polluted prototype chain.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially enable remote code execution in certain environments. While the immediate effect often manifests as application instability or unexpected behavior due to prototype contamination, sophisticated attackers can leverage this flaw to manipulate object behavior and potentially execute arbitrary code within the application context. The vulnerability's severity escalates when applications use the polluted objects in contexts that evaluate or interpret object properties dynamically, creating opportunities for code injection attacks.
According to CWE classification, this represents a variant of CWE-471: "Modification of Externally-Controlled Data Structure," which specifically addresses vulnerabilities where attacker-controlled data is used to modify data structures in unexpected ways. The ATT&CK framework categorizes this under T1059.007: "Command and Scripting Interpreter: JavaScript," as exploitation typically involves crafting malicious JavaScript payloads that leverage prototype pollution to achieve execution goals.
Mitigation strategies should begin with immediate version upgrades to patched releases of cache-base, as vendors have released updates that properly sanitize object property names during processing operations. Organizations must implement comprehensive input validation at all application boundaries where cache-base operations occur, particularly focusing on preventing prototype-polluting keys from entering the system. Additional protective measures include implementing strict object property restrictions, using secure coding practices that avoid direct object assignment with untrusted data, and deploying runtime monitoring solutions that can detect anomalous prototype modifications.
The vulnerability demonstrates how seemingly innocuous library components can create cascading security issues throughout complex application ecosystems, highlighting the importance of thorough dependency auditing and continuous security monitoring. Organizations should conduct comprehensive vulnerability assessments across their entire software supply chain to identify similar patterns in other dependencies, as prototype pollution represents a common class of vulnerabilities affecting numerous JavaScript libraries and frameworks.