CVE-2018-0500

Curl_smtp_escape_eob in lib/smtp.c in curl 7.54.1 to and including curl 7.60.0 has a heap-based buffer overflow that might be exploitable by an attacker who can control the data that curl transmits over SMTP with certain settings (i.e., use of a nonstandard --limit-rate argument or CURLOPT_BUFFERSIZE value).

Curl_smtp_escape_eob in lib/smtp.c in curl 7.54.1 to and including curl 7.60.0 has a heap-based buffer overflow that might be exploitable by an attacker who can control the data that curl transmits over SMTP with certain settings (i.e., use of a nonstandard --limit-rate argument or CURLOPT_BUFFERSIZE value).

Curl_smtp_escape_eob in lib/smtp.c in curl 7.54.1 to and including curl 7.60.0 has a heap-based buffer overflow that might be exploitable by an attacker who can control the data that curl transmits over SMTP with certain settings (i.e., use of a nonstandard --limit-rate argument or CURLOPT_BUFFERSIZE value).

curl might overflow a heap based memory buffer when sending data over SMTP and using a reduced read buffer.

When sending data over SMTP, curl allocates a separate "scratch area" on the heap to be able to escape the uploaded data properly if the uploaded data contains data that requires it.

The size of this temporary scratch area was mistakenly made to be 2 * sizeof(download_buffer) when it should have been made 2 * sizeof(upload_buffer).

The upload and the download buffer sizes are identically sized by default (16KB) but since version 7.54.1, curl can resize the download buffer into a smaller buffer (as well as larger). If the download buffer size is set to a value smaller than 10923, the Curl_smtp_escape_eob() function might overflow the scratch buffer when sending contents of sufficient size and contents.

The curl command line tool lowers the buffer size when --limit-rate is set to a value smaller than 16KB.

Updated curl packages fix security vulnerabilities:

Peter Wu discovered that curl incorrectly handled certain SMTP buffers. A remote attacker could use this issue to cause curl to crash, resulting in a denial of service, or possibly execute arbitrary code (CVE-2018-0500).

Zhaoyang Wu discovered that cURL, an URL transfer library, contains a buffer overflow in the NTLM authentication code triggered by passwords that exceed 2GB in length on 32bit systems (CVE-2018-14618).

Phan Thanh discovered that curl incorrectly handled certain FTP paths. An attacker could use this to cause a denial of service or possibly execute arbitrary code (CVE-2018-1000120).

Dario Weisser discovered that curl incorrectly handled certain LDAP URLs. An attacker could possibly use this issue to cause a denial of service (CVE-2018-1000121).

Max Dymond discovered that curl incorrectly handled certain RTSP data. An attacker could possibly use this to cause a denial of service or even to get access to sensitive data (CVE-2018-1000122).

A heap-based buffer overflow can happen when closing down an FTP connection with very long server command replies. When doing FTP transfers, curl keeps a spare "closure handle" around internally that will be used when an FTP connection gets shut down since the original curl easy handle is then already removed. FTP server response data that gets cached from the original transfer might then be larger than the default buffer size (16 KB) allocated in the "closure handle", which can lead to a buffer overwrite. The contents and size of that overwrite is controllable by the server (CVE-2018-1000300).

curl can be tricked into reading data beyond the end of a heap based buffer used to store downloaded content. When servers send RTSP responses back to curl, the data starts out with a set of headers. curl parses that data to separate it into a number of headers to deal with those appropriately and to find the end of the headers that signal the start of the "body" part. The function that splits up the response into headers is called "Curl_http_readwrite_headers()" and in situations where it can't find a single header in the buffer, it might end up leaving a pointer pointing into the buffer instead of to the start of the buffer which then later on may lead to an out of buffer read when code assumes that pointer points to a full buffer size worth of memory to use. This could potentially lead to information leakage but most likely a crash/denial of service for applications if a server triggers this flaw (CVE-2018-1000301).

These are all security issues fixed in the curl-7.79.1-1.1 package on the GA media of openSUSE Tumbleweed.

This update for curl fixes the following issues:

Security issue fixed:

• CVE-2018-0500: Fix a SMTP send heap buffer overflow (bsc#1099793).

Peter Wu discovered that curl incorrectly handled certain SMTP buffers. A remote attacker could use this issue to cause curl to crash, resulting in a denial of service, or possibly execute arbitrary code.