CVE-2020-1730

A flaw was found in libssh versions before 0.8.9 and before 0.9.4 in the way it handled AES-CTR (or DES ciphers if enabled) ciphers. The server or client could crash when the connection hasn't been fully initialized and the system tries to cleanup the ciphers when closing the connection. The biggest threat from this vulnerability is system availability.

A flaw was found in libssh versions before 0.8.9 and before 0.9.4 in the way it handled AES-CTR (or DES ciphers if enabled) ciphers. The server or client could crash when the connection hasn't been fully initialized and the system tries to cleanup the ciphers when closing the connection. The biggest threat from this vulnerability is system availability.

libssh is a library which implements the SSH protocol. It can be used to implement client and server applications.

The following packages have been upgraded to a later upstream version: libssh (0.9.4). (BZ#1804797)

Security Fix(es):

• libssh: denial of service when handling AES-CTR (or DES) ciphers (CVE-2020-1730)

• libssh: unsanitized location in scp could lead to unwanted command execution (CVE-2019-14889)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Additional Changes:

For detailed information on changes in this release, see the Rocky Linux 8.3 Release Notes linked from the References section.

A flaw was found in libssh versions before 0.8.9 and before 0.9.4 in the way it handled AES-CTR (or DES ciphers if enabled) ciphers. The server or client could crash when the connection hasn't been fully initialized and the system tries to cleanup the ciphers when closing the connection. The biggest threat from this vulnerability is system availability.

Updated libssh packages fix security vulnerability:

A malicious client or server could crash the counterpart implemented with libssh AES-CTR ciphers are used and don't get fully initialized. It will crash when it tries to cleanup the AES-CTR ciphers when closing the connection (CVE-2020-1730).

This update for libssh fixes the following issues:

• CVE-2020-1730: Fixed a possible denial of service when using AES-CTR (bsc#1168699).

This update was imported from the SUSE:SLE-15-SP1:Update update project.

These are all security issues fixed in the libssh-config-0.9.6-2.1 package on the GA media of openSUSE Tumbleweed.

This update for libssh fixes the following issues:

• CVE-2020-1730: Fixed a possible denial of service when using AES-CTR (bsc#1168699).

This update for libssh fixes the following issues:

• CVE-2020-1730: Fixed a possible denial of service when using AES-CTR (bsc#1168699).

This update for libssh fixes the following issues:

Update to version 0.9.8 (jsc#PED-7719):

• Fix CVE-2023-6004: Command injection using proxycommand (bsc#1218209)
• Fix CVE-2023-48795: Potential downgrade attack using strict kex (bsc#1218126)
• Fix CVE-2023-6918: Missing checks for return values of MD functions (bsc#1218186)
• Allow @ in usernames when parsing from URI composes

Update to version 0.9.7:

• Fix CVE-2023-1667: a NULL dereference during rekeying with algorithm guessing (bsc#1211188)
• Fix CVE-2023-2283: a possible authorization bypass in pki_verify_data_signature under low-memory conditions (bsc#1211190)
• Fix several memory leaks in GSSAPI handling code

Update to version 0.9.6 (bsc#1189608, CVE-2021-3634):

• https://git.libssh.org/projects/libssh.git/tag/?h=libssh-0.9.6

Update to 0.9.5 (bsc#1174713, CVE-2020-16135):

• CVE-2020-16135: Avoid null pointer dereference in sftpserver (T232)
• Improve handling of library initialization (T222)
• Fix parsing of subsecond times in SFTP (T219)
• Make the documentation reproducible
• Remove deprecated API usage in OpenSSL
• Fix regression of ssh_channel_poll_timeout() returning SSH_AGAIN
• Define version in one place (T226)
• Prevent invalid free when using different C runtimes than OpenSSL (T229)
• Compatibility improvements to testsuite

Update to version 0.9.4

• https://www.libssh.org/2020/04/09/libssh-0-9-4-and-libssh-0-8-9-security-release/
• Fix possible Denial of Service attack when using AES-CTR-ciphers CVE-2020-1730 (bsc#1168699)

Update to version 0.9.3

• Fixed CVE-2019-14889 - SCP: Unsanitized location leads to command execution (bsc#1158095)
• SSH-01-003 Client: Missing NULL check leads to crash in erroneous state
• SSH-01-006 General: Various unchecked Null-derefs cause DOS
• SSH-01-007 PKI Gcrypt: Potential UAF/double free with RSA pubkeys
• SSH-01-010 SSH: Deprecated hash function in fingerprinting
• SSH-01-013 Conf-Parsing: Recursive wildcards in hostnames lead to DOS
• SSH-01-014 Conf-Parsing: Integer underflow leads to OOB array access
• SSH-01-001 State Machine: Initial machine states should be set explicitly
• SSH-01-002 Kex: Differently bound macros used to iterate same array
• SSH-01-005 Code-Quality: Integer sign confusion during assignments
• SSH-01-008 SCP: Protocol Injection via unescaped File Names
• SSH-01-009 SSH: Update documentation which RFCs are implemented
• SSH-01-012 PKI: Information leak via uninitialized stack buffer

Update to version 0.9.2

• Fixed libssh-config.cmake
• Fixed issues with rsa algorithm negotiation (T191)
• Fixed detection of OpenSSL ed25519 support (T197)

Update to version 0.9.1

• Added support for Ed25519 via OpenSSL
• Added support for X25519 via OpenSSL
• Added support for localuser in Match keyword
• Fixed Match keyword to be case sensitive
• Fixed compilation with LibreSSL
• Fixed error report of channel open (T75)
• Fixed sftp documentation (T137)
• Fixed known_hosts parsing (T156)
• Fixed build issue with MinGW (T157)
• Fixed build with gcc 9 (T164)
• Fixed deprecation issues (T165)
• Fixed known_hosts directory creation (T166)

• Split out configuration to separate package to not mess up the library packaging and coinstallation

Update to verion 0.9.0

• Added support for AES-GCM
• Added improved rekeying support
• Added performance improvements
• Disabled blowfish support by default
• Fixed several ssh config parsing issues
• Added support for DH Group Exchange KEX
• Added support for Encrypt-then-MAC mode
• Added support for parsing server side configuration file
• Added support for ECDSA/Ed25519 certificates
• Added FIPS 140-2 compatibility
• Improved known_hosts parsing
• Improved documentation
• Improved OpenSSL API usage for KEX, DH, and signatures

• Add libssh client and server config files

This update for libssh fixes the following issues:

Update to version 0.9.8 (jsc#PED-7719):

• Fix CVE-2023-6004: Command injection using proxycommand (bsc#1218209)
• Fix CVE-2023-48795: Potential downgrade attack using strict kex (bsc#1218126)
• Fix CVE-2023-6918: Missing checks for return values of MD functions (bsc#1218186)
• Allow @ in usernames when parsing from URI composes

Update to version 0.9.7

• Fix CVE-2023-1667: a NULL dereference during rekeying with algorithm guessing (bsc#1211188)
• Fix CVE-2023-2283: a possible authorization bypass in pki_verify_data_signature under low-memory conditions (bsc#1211190)
• Fix several memory leaks in GSSAPI handling code

Update to version 0.9.6 (bsc#1189608, CVE-2021-3634)

• https://git.libssh.org/projects/libssh.git/tag/?h=libssh-0.9.6

Update to version 0.9.5 (bsc#1174713, CVE-2020-16135):

• CVE-2020-16135: Avoid null pointer dereference in sftpserver (T232)
• Improve handling of library initialization (T222)
• Fix parsing of subsecond times in SFTP (T219)
• Make the documentation reproducible
• Remove deprecated API usage in OpenSSL
• Fix regression of ssh_channel_poll_timeout() returning SSH_AGAIN
• Define version in one place (T226)
• Prevent invalid free when using different C runtimes than OpenSSL (T229)
• Compatibility improvements to testsuite

Update to version 0.9.4:

• https://www.libssh.org/2020/04/09/libssh-0-9-4-and-libssh-0-8-9-security-release/
• Fix possible Denial of Service attack when using AES-CTR-ciphers CVE-2020-1730 (bsc#1168699)

Update to version 0.9.3:

• Fixed CVE-2019-14889 - SCP: Unsanitized location leads to command execution (bsc#1158095)
• SSH-01-003 Client: Missing NULL check leads to crash in erroneous state
• SSH-01-006 General: Various unchecked Null-derefs cause DOS
• SSH-01-007 PKI Gcrypt: Potential UAF/double free with RSA pubkeys
• SSH-01-010 SSH: Deprecated hash function in fingerprinting
• SSH-01-013 Conf-Parsing: Recursive wildcards in hostnames lead to DOS
• SSH-01-014 Conf-Parsing: Integer underflow leads to OOB array access
• SSH-01-001 State Machine: Initial machine states should be set explicitly
• SSH-01-002 Kex: Differently bound macros used to iterate same array
• SSH-01-005 Code-Quality: Integer sign confusion during assignments
• SSH-01-008 SCP: Protocol Injection via unescaped File Names
• SSH-01-009 SSH: Update documentation which RFCs are implemented
• SSH-01-012 PKI: Information leak via uninitialized stack buffer

Update to version 0.9.2:

• Fixed libssh-config.cmake
• Fixed issues with rsa algorithm negotiation (T191)
• Fixed detection of OpenSSL ed25519 support (T197)

Update to version 0.9.1:

• Added support for Ed25519 via OpenSSL
• Added support for X25519 via OpenSSL
• Added support for localuser in Match keyword
• Fixed Match keyword to be case sensitive
• Fixed compilation with LibreSSL
• Fixed error report of channel open (T75)
• Fixed sftp documentation (T137)
• Fixed known_hosts parsing (T156)
• Fixed build issue with MinGW (T157)
• Fixed build with gcc 9 (T164)
• Fixed deprecation issues (T165)
• Fixed known_hosts directory creation (T166)

Update to verion 0.9.0:

• Added support for AES-GCM
• Added improved rekeying support
• Added performance improvements
• Disabled blowfish support by default
• Fixed several ssh config parsing issues
• Added support for DH Group Exchange KEX
• Added support for Encrypt-then-MAC mode
• Added support for parsing server side configuration file
• Added support for ECDSA/Ed25519 certificates
• Added FIPS 140-2 compatibility
• Improved known_hosts parsing
• Improved documentation
• Improved OpenSSL API usage for KEX, DH, and signatures

• Add libssh client and server config files

Yasheng Yang discovered that libssh incorrectly handled AES-CTR ciphers. A remote attacker could possibly use this issue to cause libssh to crash, resulting in a denial of service.