Node.js vulnerabilities

A flaw in Node.js's buffer allocation logic can expose uninitialized memory when allocations are interrupted, when using the `vm` module with the timeout option. Under specific timing conditions, buffers allocated with `Buffer.alloc` and other `TypedArray` instances like `Uint8Array` may contain leftover data from previous operations, allowing in-process secrets like tokens or passwords to leak or causing data corruption.

The generateKeys() API function returned from crypto.createDiffieHellman() only generates missing (or outdated) keys, that is, it only generates a private key if none has been set yet, but the function is also needed to compute the corresponding public key after calling setPrivateKey(). However, the documentation says this API call: "Generates private and public Diffie-Hellman key values". The documented behavior is very different from the actual behavior, and this difference could easily lead to security issues in applications that use these APIs as the DiffieHellman may be used as the basis for application-level security, implications are consequently broad.

A vulnerability has been identified in the Node.js (.msi version) installation process, specifically affecting Windows users who install Node.js using the .msi installer. This vulnerability emerges during the repair operation, where the "msiexec.exe" process, running under the NT AUTHORITY\SYSTEM context, attempts to read the %USERPROFILE% environment variable from the current user's registry. The issue arises when the path referenced by the %USERPROFILE% environment variable does not exist. In such cases, the "msiexec.exe" process attempts to create the specified path in an unsafe manner, potentially leading to the creation of arbitrary folders in arbitrary locations. The severity of this vulnerability is heightened by the fact that the %USERPROFILE% environment variable in the Windows registry can be modified by standard (or "non-privileged") users. Consequently, unprivileged actors, including malicious entities or trojans, can manipulate the environment variable key to deceive the privileged "msiexec.exe" process. This manipulation can result in the creation of folders in unintended and potentially malicious locations. It is important to note that this vulnerability is specific to Windows users who install Node.js using the .msi installer. Users who opt for other installation methods are not affected by this particular issue.

A remote attacker can trigger a denial of service in the socket.remoteAddress variable by sending a crafted HTTP request. Usage of the undefined variable raises a TypeError exception.

In all versions of Node.js 10 prior to 10.9.0, an argument processing flaw can cause `Buffer.alloc()` to return uninitialized memory. This method is intended to be safe and only return initialized, or cleared, memory. The third argument specifying `encoding` can be passed as a number, this is misinterpreted by `Buffer's` internal "fill" method as the `start` to a fill operation. This flaw may be abused where `Buffer.alloc()` arguments are derived from user input to return uncleared memory blocks that may contain sensitive information.

The HTTP parser in all current versions of Node.js ignores spaces in the Content-Length header, allowing input such as 'Content-Length: 1 2' to be interpreted as having a value of '12'. The HTTP specification does not allow for spaces in the Content-Length value and the Node.js HTTP parser has been brought into line on this particular difference. The security risk of this flaw to Node.js users is considered to be VERY LOW as it is difficult, and may be impossible, to craft an attack that makes use of this flaw in a way that could not already be achieved by supplying an incorrect value for Content-Length. Vulnerabilities may exist in user-code that make incorrect assumptions about the potential accuracy of this value compared to the actual length of the data supplied. Node.js users crafting lower-level HTTP utilities are advised to re-check the length of any input supplied after parsing is complete.

The `'path'` module in the Node.js 4.x release line contains a potential regular expression denial of service (ReDoS) vector. The code in question was replaced in Node.js 6.x and later so this vulnerability only impacts all versions of Node.js 4.x. The regular expression, `splitPathRe`, used within the `'path'` module for the various path parsing functions, including `path.dirname()`, `path.extname()` and `path.parse()` was structured in such a way as to allow an attacker to craft a string, that when passed through one of these functions, could take a significant amount of time to evaluate, potentially leading to a full denial of service.