CVE-2017-1000254

libcurl may read outside of a heap allocated buffer when doing FTP. When libcurl connects to an FTP server and successfully logs in (anonymous or not), it asks the server for the current directory with the PWD command. The server then responds with a 257 response containing the path, inside double quotes. The returned path name is then kept by libcurl for subsequent uses. Due to a flaw in the string parser for this directory name, a directory name passed like this but without a closing double quote would lead to libcurl not adding a trailing NUL byte to the buffer holding the name. When libcurl would then later access the string, it could read beyond the allocated heap buffer and crash or wrongly access data beyond the buffer, thinking it was part of the path. A malicious server could abuse this fact and effectively prevent libcurl-based clients to work with it - the PWD command is always issued on new FTP connections and the mistake has a high chance of causing a segfault. The simple fact that this has issue remained undiscovered for this long could suggest that malformed PWD responses are rare in benign servers. We are not aware of any exploit of this flaw. This bug was introduced in commit 415d2e7cb7, March 2005. In libcurl version 7.56.0, the parser always zero terminates the string but also rejects it if not terminated properly with a final double quote.

libcurl may read outside of a heap allocated buffer when doing FTP. When libcurl connects to an FTP server and successfully logs in (anonymous or not), it asks the server for the current directory with the PWD command. The server then responds with a 257 response containing the path, inside double quotes. The returned path name is then kept by libcurl for subsequent uses. Due to a flaw in the string parser for this directory name, a directory name passed like this but without a closing double quote would lead to libcurl not adding a trailing NUL byte to the buffer holding the name. When libcurl would then later access the string, it could read beyond the allocated heap buffer and crash or wrongly access data beyond the buffer, thinking it was part of the path. A malicious server could abuse this fact and effectively prevent libcurl-based clients to work with it - the PWD command is always issued on new FTP connections and the mistake has a high chance of causing a segfault. The simple fact that this has issue remained undiscovered for this long could suggest that malformed PWD responses are rare in benign servers. We are not aware of any exploit of this flaw. This bug was introduced in commit 415d2e7cb7, March 2005. In libcurl version 7.56.0, the parser always zero terminates the string but also rejects it if not terminated properly with a final double quote.

libcurl may read outside of a heap allocated buffer when doing FTP. When libcurl connects to an FTP server and successfully logs in (anonymous or not), it asks the server for the current directory with the PWD command. The server then responds with a 257 response containing the path, inside double quotes. The returned path name is then kept by libcurl for subsequent uses. Due to a flaw in the string parser for this directory name, a directory name passed like this but without a closing double quote would lead to libcurl not adding a trailing NUL byte to the buffer holding the name. When libcurl would then later access the string, it could read beyond the allocated heap buffer and crash or wrongly access data beyond the buffer, thinking it was part of the path. A malicious server could abuse this fact and effectively prevent libcurl-based clients to work with it - the PWD command is always issued on new FTP connections and the mistake has a high chance of causing a segfault. The simple fact that this has issue remained undiscovered for this long could suggest that malformed PWD responses are rare in benign servers. We are not aware of any exploit of this flaw. This bug was introduced in commit 415d2e7cb7, March 2005. In libcurl version 7.56.0, the parser always zero terminates the string but also rejects it if not terminated properly with a final double quote.

libcurl may read outside of a heap allocated buffer when doing FTP.

When libcurl connects to an FTP server and successfully logs in (anonymous or not), it asks the server for the current directory with the PWD command. The server then responds with a 257 response containing the path, inside double quotes. The returned path name is then kept by libcurl for subsequent uses.

Due to a flaw in the string parser for this directory name, a directory name passed like this but without a closing double quote would lead to libcurl not adding a trailing null byte to the buffer holding the name. When libcurl would then later access the string, it could read beyond the allocated heap buffer and crash or wrongly access data beyond the buffer, thinking it was part of the path.

A malicious server could abuse this fact and effectively prevent libcurl-based clients to work with it - the PWD command is always issued on new FTP connections and the mistake has a high chance of causing a segfault.

The simple fact that this issue has remained undiscovered for this long could suggest that malformed PWD responses are rare in benign servers.

If cookie state is written into a cookie jar file that is later read back and used for subsequent requests, a malicious HTTP server can inject new cookies for arbitrary domains into said cookie jar. The issue pertains to the function that loads cookies into memory, which reads the specified file into a fixed-size buffer in a line-by-line manner using the fgets() function. If an invocation of fgets() cannot read the whole line into the destination buffer due to it being too small, it truncates the output. This way, a very long cookie (name + value) sent by a malicious server would be stored in the file and subsequently that cookie could be read partially and crafted correctly, it could be treated as a different cookie for another server (CVE-2016-8615).

When re-using a connection, curl was doing case insensitive comparisons of user name and password with the existing connections. This means that if an unused connection with proper credentials exists for a protocol that has connection-scoped credentials, an attacker can cause that connection to be reused if s/he knows the case-insensitive version of the correct password (CVE-2016-8616).

In libcurl's base64 encode function, the output buffer is allocated without any checks on a variable used to determine its size. On systems with 32-bit addresses in userspace, the multiplication in the expression wraps around if the size is too large. If this happens, an undersized output buffer will be allocated, but the full result will be written, thus causing the memory behind the output buffer to be overwritten. If a username is set directly via CURLOPT_USERNAME (or curl's -u, --user option), this vulnerability can be triggered. The name has to be at least 512MB big in a 32bit system. Systems with 64 bit versions of the size_t type are not affected by this issue (CVE-2016-8617).

The libcurl API function called curl_maprintf() can be tricked into doing a double-free due to an unsafe size_t multiplication, on systems using 32 bit size_t variables. The function is also used internallty in numerous situations. The function doubles an allocated memory area with realloc() and allows the size to wrap and become zero and when doing so realloc() returns NULL and frees the memory - in contrary to normal realloc() fails where it only returns NULL - causing libcurl to free the memory again in the error path. Systems with 64 bit versions of the size_t type are not affected by this issue. This behavior is triggable using the publicly exposed function (CVE-2016-8618).

In curl's implementation of the Kerberos authentication mechanism, the function read_data() in security.c is used to fill the necessary krb5 structures. When reading one of the length fields from the socket, it fails to ensure that the length parameter passed to realloc() is not set to 0. This would lead to realloc() getting called with a zero size and when doing so realloc() returns NULL and frees the memory - in contrary to normal realloc() fails where it only returns NULL - causing libcurl to free the memory again in the error path. This flaw could be triggered by a malicious or just otherwise ill-behaving server (CVE-2016-8619).

The curl tool's "globbing" feature allows a user to specify a numerical range through which curl will iterate. The curl code for parsing the second unsigned number did not check for a leading minus character, which allowed a user to specify [1--1] with no complaints and have the latter -1 number get turned into the largest unsigned long value the system can handle. This would ultimately cause curl to write outside the dedicated malloced buffer after no less than 100,000 iterations, since it would have room for 5 digits but not 6. When the range is specified with letters, and the ending letter is left out [L-], the code would still advance its read pointer 5 bytes even if the string was just 4 bytes and end up reading outside the given buffer. This flaw exists only in the curl tool, not in the libcurl library…

libcurl contains a buffer overrun flaw in the NTLM authentication code (CVE-2017-8816).

libcurl contains a read out of bounds flaw in the FTP wildcard function (CVE-2017-8817).

libcurl may read outside of a heap allocated buffer when doing FTP (CVE-2017-1000254).

libcurl contains a buffer overrun flaw in the IMAP handler (CVE-2017-1000257).

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 security issues:

• CVE-2017-1000254: FTP PWD response parser out of bounds read (bsc#1061876)

This update for curl fixes the following issues:

Security issues fixed:

• CVE-2017-1000254: FTP PWD response parser out of bounds read (bsc#1061876)
• CVE-2017-1000257: IMAP FETCH response out of bounds read (bsc#1063824)

Bugs fixed:

• Fixed error 'error:1408F10B:SSL routines' when connecting to ftps via proxy (bsc#1060653)

This update for curl fixes the following security issues:

• CVE-2017-1000254: FTP PWD response parser out of bounds read (bsc#1061876)

This update for curl fixes several issues.

These security issues were fixed:

• CVE-2017-1000254: Fix FTP PWD response parser out of bounds read (bsc#1061876).
• CVE-2018-1000007: Prevent leaking authentication data to third parties when following redirects (bsc#1077001)

Also the following adjustment was made:

• Set DEFAULT_SUSE as the default cipher list (bsc#1027712)

Daniel Stenberg discovered that curl incorrectly handled large floating point output. A remote attacker could use this issue to cause curl to crash, resulting in a denial of service, or possibly execute arbitrary code. This issue only affected Ubuntu 14.04 LTS and Ubuntu 16.04 LTS. (CVE-2016-9586)

Even Rouault discovered that curl incorrectly handled large file names when doing TFTP transfers. A remote attacker could use this issue to cause curl to crash, resulting in a denial of service, or possibly obtain sensitive memory contents. (CVE-2017-1000100)

Brian Carpenter and Yongji Ouyang discovered that curl incorrectly handled numerical range globbing. A remote attacker could use this issue to cause curl to crash, resulting in a denial of service, or possibly obtain sensitive memory contents. (CVE-2017-1000101)

Max Dymond discovered that curl incorrectly handled FTP PWD responses. A remote attacker could use this issue to cause curl to crash, resulting in a denial of service. (CVE-2017-1000254)

Brian Carpenter discovered that curl incorrectly handled the --write-out command line option. A local attacker could possibly use this issue to obtain sensitive memory contents. (CVE-2017-7407)