The product uses external input to construct a pathname that should be within a restricted directory, but it does not properly neutralize '....' (multiple dot) 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. On some Windows systems, it is equivalent to "......" and might bypass checks that assume only two dots are valid. Incomplete filtering, such as removal of "./" sequences, can ultimately produce valid ".." sequences due to a collapse into unsafe value (CWE-182).
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.
Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)
CVE-2000-0240read files via "/........../" in URL
CVE-2000-0773read files via "...." in web server
CVE-1999-1082read files via "......" in web server (doubled triple dot?)
CVE-2004-2121read files via "......" in web server (doubled triple dot?)
CVE-2001-0491multiple attacks using "..", "...", and "...." in different commands