(RHSA-2015:2159) Moderate: curl security, bug fix, and enhancement update

The curl packages provide the libcurl library and the curl utility for
downloading files from servers using various protocols, including HTTP,
FTP, and LDAP.

It was found that the libcurl library did not correctly handle partial
literal IP addresses when parsing received HTTP cookies. An attacker able
to trick a user into connecting to a malicious server could use this flaw
to set the user’s cookie to a crafted domain, making other cookie-related
issues easier to exploit. (CVE-2014-3613)

A flaw was found in the way the libcurl library performed the duplication
of connection handles. If an application set the CURLOPT_COPYPOSTFIELDS
option for a handle, using the handle’s duplicate could cause the
application to crash or disclose a portion of its memory. (CVE-2014-3707)

It was discovered that the libcurl library failed to properly handle URLs
with embedded end-of-line characters. An attacker able to make an
application using libcurl access a specially crafted URL via an HTTP proxy
could use this flaw to inject additional headers to the request or
construct additional requests. (CVE-2014-8150)

It was discovered that libcurl implemented aspects of the NTLM and
Negotatiate authentication incorrectly. If an application uses libcurl
and the affected mechanisms in a specifc way, certain requests to a
previously NTLM-authenticated server could appears as sent by the wrong
authenticated user. Additionally, the initial set of credentials for HTTP
Negotiate-authenticated requests could be reused in subsequent requests,
although a different set of credentials was specified. (CVE-2015-3143,
CVE-2015-3148)

Red Hat would like to thank the cURL project for reporting these issues.

Bug fixes:

• An out-of-protocol fallback to SSL 3.0 was available with libcurl.
  Attackers could abuse the fallback to force downgrade of the SSL version.
  The fallback has been removed from libcurl. Users requiring this
  functionality can explicitly enable SSL 3.0 through the libcurl API.
  (BZ#1154060)

• TLS 1.1 and TLS 1.2 are no longer disabled by default in libcurl. You can
  explicitly disable them through the libcurl API. (BZ#1170339)

• FTP operations such as downloading files took a significantly long time
  to complete. Now, the FTP implementation in libcurl correctly sets blocking
  direction and estimated timeout for connections, resulting in faster FTP
  transfers. (BZ#1218272)

Enhancements:

• With the updated packages, it is possible to explicitly enable or disable
  new Advanced Encryption Standard (AES) cipher suites to be used for the TLS
  protocol. (BZ#1066065)

• The libcurl library did not implement a non-blocking SSL handshake, which
  negatively affected performance of applications based on the libcurl multi
  API. The non-blocking SSL handshake has been implemented in libcurl, and
  the libcurl multi API now immediately returns the control back to the
  application whenever it cannot read or write data from or to the underlying
  network socket. (BZ#1091429)

• The libcurl library used an unnecessarily long blocking delay for actions
  with no active file descriptors, even for short operations. Some actions,
  such as resolving a host name using /etc/hosts, took a long time to
  complete. The blocking code in libcurl has been modified so that the
  initial delay is short and gradually increases until an event occurs.
  (BZ#1130239)

All curl users are advised to upgrade to these updated packages, which
contain backported patches to correct these issues and add these
enhancements.