The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize '....//' (doubled dot dot slash) sequences that can resolve to a location that is outside of that directory.
This allows attackers to traverse the file system to access files or directories that are outside of the restricted directory.
The '....//' manipulation is useful for bypassing some path traversal protection schemes. If "../" is filtered in a sequential fashion, as done by some regular expression engines, then "....//" can collapse into the "../" unsafe value (CWE-182). It could also be useful when ".." is removed, if the operating system treats "//" and "/" as equivalent.
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conf...
Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.
According to SOAR [REF-1479], the following detection techniques may be useful:
According to SOAR [REF-1479], the following detection techniques may be useful: