CVE-2017-1000257

Source
Severity Medium
Remote Yes
Type Information disclosure
Description
A heap buffer overrun flaw was found in the IMAP handler of libcurl >= 7.20.0 and < 7.56.1. An IMAP FETCH response line indicates the size of the returned data, in number of bytes. When that response says the data is zero bytes, libcurl would pass on that (non-existing) data with a pointer and the size (zero) to the deliver-data function. libcurl's deliver-data function treats zero as a magic number and invokes strlen() on the data to figure out the length. The strlen() is called on a heap based buffer that might not be zero terminated so libcurl might read beyond the end of it into whatever memory lies after (or just crash) and then deliver that to the application as if it was actually downloaded.
By tricking an unsuspecting user into connecting to a malicious IMAP server, an attacker could exploit this flaw to potentially cause information disclosure or crash the application.
Group Package Affected Fixed Severity Status Ticket
AVG-467 curl 7.56.0-1 7.56.1-1 Medium Fixed
AVG-466 lib32-curl 7.56.0-1 7.56.1-1 Medium Fixed
AVG-465 lib32-libcurl-compat 7.56.0-1 7.56.1-1 Medium Fixed
AVG-464 lib32-libcurl-gnutls 7.56.0-1 7.56.1-1 Medium Fixed
AVG-463 libcurl-compat 7.56.0-1 7.56.1-1 Medium Fixed
AVG-462 libcurl-gnutls 7.56.0-1 7.56.1-1 Medium Fixed
Date Advisory Group Package Severity Description
02 Nov 2017 ASA-201711-9 AVG-464 lib32-libcurl-gnutls Medium information disclosure
02 Nov 2017 ASA-201711-8 AVG-465 lib32-libcurl-compat Medium information disclosure
02 Nov 2017 ASA-201711-7 AVG-466 lib32-curl Medium information disclosure
02 Nov 2017 ASA-201711-6 AVG-467 curl Medium information disclosure
02 Nov 2017 ASA-201711-11 AVG-462 libcurl-gnutls Medium information disclosure
02 Nov 2017 ASA-201711-10 AVG-463 libcurl-compat Medium information disclosure
References
https://curl.haxx.se/docs/adv_20171023.html
https://curl.haxx.se/CVE-2017-1000257.patch
https://github.com/curl/curl/commit/13c9a9ded3ae744a1e11cbc14e9146d9fa427040
Notes
Introduced by: https://github.com/curl/curl/commit/ec3bb8f727405642a471b4b1b9eb0118fc003104