[SECURITY ADVISORY] curl: URL globbing out of bounds read

[Daniel Stenberg]

URL globbing out of bounds read
===============================

Project curl Security Advisory, August 9th 2017 -
[Permalink](https://curl.haxx.se/docs/adv_20170809A.html)

VULNERABILITY
-------------

curl supports "globbing" of URLs, in which a user can pass a numerical range
to have the tool iterate over those numbers to do a sequence of transfers.

In the globbing function that parses the numerical range, there was an
omission that made curl read a byte beyond the end of the URL if given a
carefully crafted, or just wrongly written, URL. The URL is stored in a heap
based buffer, so it could then be made to wrongly read something else instead
of crashing.

An example of a URL that triggers the flaw would be
`http://ur%20[0-60000000000000000000`.

We are not aware of any exploit of this flaw.

INFO
----

This flaw only affects the curl command line tool, not the libcurl
library. The bug was introduced in commit
[5ca96cb84410270](https://github.com/curl/curl/commit/5ca96cb84410270), August
2013. curl 7.34.0.

For version 7.55.0, the parser properly stops at the end of the string and a
test has been added to verify this.

The Common Vulnerabilities and Exposures (CVE) project has assigned the name
CVE-2017-1000101 to this issue.

AFFECTED VERSIONS
-----------------

- Affected versions: curl 7.34.0 to and including 7.54.1
- Not affected versions: curl < 7.34.0 and >= 7.55.1

curl is used by many applications, but not always advertised as such.

THE SOLUTION
------------

A [patch for CVE-2017-1000101](https://curl.haxx.se/CVE-2017-1000101.patch) is
available.

RECOMMENDATIONS
---------------

We suggest you take one of the following actions immediately, in order of
preference:

A - Upgrade curl to version 7.55.0

B - Apply the patch to your version and rebuild

TIME LINE
---------

It was reported to the curl project on June 14, 2017. We contacted
***@openwall on August 1.

curl 7.55.0 was released on August 9 2017, coordinated with the publication of
this advisory.

CREDITS
-------

Reported by Brian Carpenter and Yongji Ouyang (independently of each
other). Patch by Daniel Stenberg.

Thanks a lot!