9ce55146c8
This fixes a reported Stored XSS vulnerability in toBloodhoundJson by
encoding the user-controlled values in this payload into base64 and
parsing them with atob.
In my exploration of the vulnerability with various payloads I and
others crafted, it would appear that this is the only available XSS in
hledger-web in relation to stored accounts and transaction details. If
there is other parts of the UI which may contain user-controlled data,
they should be examined for similar things. In this instance,
protections provided by yesod and other libraries worked fine, but in a
bit of code that hledger-web was generating, the user could insert a
</Script> tag (which is valid HTML and equivalent to </script> but not
caught by the T.Replace that existed in toBloodhoundJson) in order to
switch out of a script context, allowing the parser to be reset, and for
arbitrary JavaScript to run.
The real fix is a bit more involved, but produces much better results:
Content-Security-Policy headers should be introduced, and using
sha256-<hash of script> or a different algorithm, they should be marked
as trusted in the header. This way, if the (in-browser) parser and
hledger-web generator disagree on the source code of the script, the
script won't run. Note that this would still be susceptible to attacks
that involve changing the script by escaping from the string inside it
or something similar to that, which can be avoided additionally by using
either the method used in this commit, or a proper JSON encoder.
The second approach has the advantage of preventing further XSS, to the
extent specified above, in practice, a combination of both should be
used, b64 for embedded data and the CSP sha256-hash script-src over
everything else, which will eliminate all injected or malformed script
blocks (via CSP), in combination with eliminating any HTML closing tags
which might occur in stored data (via b64).
This vulnerability appears to have been first introduced when
autocompletion was added in hledger-web, git tag hledger-0.24, commit
hash:
|
||
|---|---|---|
| .github | ||
| .sandstorm | ||
| bin | ||
| checks | ||
| doc | ||
| docker | ||
| docker-static-arm32v7 | ||
| examples | ||
| hledger | ||
| hledger-install | ||
| hledger-lib | ||
| hledger-ui | ||
| hledger-web | ||
| tools | ||
| .ci | ||
| .ctags | ||
| .dockerignore | ||
| .editorconfig | ||
| .ghci | ||
| .gitignore | ||
| .hlint.yaml | ||
| .mailmap | ||
| .version | ||
| azure-pipelines.yml | ||
| bench.sh | ||
| cabal.project | ||
| CHANGES.md | ||
| CONTRIBUTING.md | ||
| CREDITS.md | ||
| dev.hs | ||
| dir | ||
| Dockerfile | ||
| hie.yaml | ||
| LICENSE | ||
| Makefile | ||
| Makefile.helpsys | ||
| README.md | ||
| RELEASING.md | ||
| ROADMAP.md | ||
| Shake.hs | ||
| stack8.6.yaml | ||
| stack8.8.yaml | ||
| stack8.10.yaml | ||
| stack.yaml | ||
hledger project README
lightweight, portable, dependable accounting tools
hledger is a computer program for easily tracking money, time, or other commodities, on unix, mac and windows (and web-capable mobile devices, to some extent).
It is first a command-line tool, but there are also terminal and web interfaces, and a Haskell library for building your own programs and scripts (hledger is written in Haskell). hledger was inspired by and is largely compatible with Ledger. hledger is free software available under the GNU General Public License v3+.
hledger aims to help both computer experts and regular folks to gain clarity and control in their finances and time management, but currently it is a bit more suited to techies. I use it every day to:
- track spending and income
- see time reports by day/week/month/project
- get accurate numbers for client billing and tax filing
- track invoices
Though limited in features, hledger is lightweight, usable and reliable. For some, it is a simpler, less distracting, more future-proof alternative to Quicken or GnuCash.
For more, see the home page: https://hledger.org
Sponsorship
Your support, large or small, helps keep this project strong!
See also https://hledger.org#sponsorship.
Sponsor Simon (project leader): 
Sponsor the hledger project as an organisation: 
Sponsor the hledger project as an individual: 
Bounties for specific tasks: 
