CVE-2021-3618

ALPACA is an application layer protocol content confusion attack, exploiting TLS servers implementing different protocols but using compatible certificates, such as multi-domain or wildcard certificates. A MiTM attacker having access to victim's traffic at the TCP/IP layer can redirect traffic from one subdomain to another, resulting in a valid TLS session. This breaks the authentication of TLS and cross-protocol attacks may be possible where the behavior of one protocol service may compromise the other at the application layer.

ALPACA is an application layer protocol content confusion attack, exploiting TLS servers implementing different protocols but using compatible certificates, such as multi-domain or wildcard certificates. A MiTM attacker having access to victim's traffic at the TCP/IP layer can redirect traffic from one subdomain to another, resulting in a valid TLS session. This breaks the authentication of TLS and cross-protocol attacks may be possible where the behavior of one protocol service may compromise the other at the application layer.

ALPACA is an application layer protocol content confusion attack, exploiting TLS servers implementing different protocols but using compatible certificates, such as multi-domain or wildcard certificates. A MiTM attacker having access to victim's traffic at the TCP/IP layer can redirect traffic from one subdomain to another, resulting in a valid TLS session. This breaks the authentication of TLS and cross-protocol attacks may be possible where the behavior of one protocol service may compromise the other at the application layer.

ALPACA is an application layer protocol content confusion attack, exploiting TLS servers implementing different protocols but using compatible certificates, such as multi-domain or wildcard certificates. A MiTM attacker having access to victim's traffic at the TCP/IP layer can redirect traffic from one subdomain to another, resulting in a valid TLS session. This breaks the authentication of TLS and cross-protocol attacks may be possible where the behavior of one protocol service may compromise the other at the application layer.

NGINX is a free, open-source, high-performance HTTP server and reverse proxy, as well as an IMAP/POP3 proxy server.

Security Fix(es): ALPACA is an application layer protocol content confusion attack, exploiting TLS servers implementing different protocols but using compatible certificates, such as multi-domain or wildcard certificates. A MiTM attacker having access to victim's traffic at the TCP/IP layer can redirect traffic from one subdomain to another, resulting in a valid TLS session. This breaks the authentication of TLS and cross-protocol attacks may be possible where the behavior of one protocol service may compromise the other at the application layer.(CVE-2021-3618)

ALPACA is an application layer protocol content confusion attack, exploiting TLS servers implementing different protocols but using compatible certificates, such as multi-domain or wildcard certificates. A MiTM attacker having access to victim's traffic at the TCP/IP layer can redirect traffic from one subdomain to another, resulting in a valid TLS session. This breaks the authentication of TLS and cross-protocol attacks may be possible where the behavior of one protocol service may compromise the other at the application layer.

ALPACA is an application layer protocol content confusion attack, exploiting TLS servers implementing different protocols but using compatible certificates, such as multi-domain or wildcard certificates. A MiTM attacker having access to victim's traffic at the TCP/IP layer can redirect traffic from one subdomain to another, resulting in a valid TLS session. This breaks the authentication of TLS and cross-protocol attacks may be possible where the behavior of one protocol service may compromise the other at the application layer.

ALPACA is an application layer protocol content confusion attack, exploiting TLS servers implementing different protocols but using compatible certificates, such as multi-domain or wildcard certificates. A MiTM attacker having access to victim's traffic at the TCP/IP layer can redirect traffic from one subdomain to another, resulting in a valid TLS session. This breaks the authentication of TLS and cross-protocol attacks may be possible where the behavior of one protocol service may compromise the other at the application layer.

• CVE-2021-3618: drop the connection after reaching the specified number of invalid protocol commmands

• SECURITY UPDATE: Vulnerability against application layer protocol content confusion attack
  • debian/patches/CVE-2021-3618.patch: Drop the connection after reaching the specified number of invalid protocol commmands
  • CVE-2021-3618

• CVE-2021-3618: drop the connection after reaching the specified number of invalid protocol commmands

• CVE-2021-3618: drop the connection after reaching the specified number of invalid protocol commmands

• CVE-2021-3618: drop the connection after reaching the specified number of invalid protocol commmands

ALPACA: Application Layer Protocol Confusion - Analyzing and Mitigating Cracks in TLS Authentication

This update for vsftpd fixes the following issues:

This update enables vsftpd to speak TLS 1.3 in ssl FTP mode by linking against openssl 1.1.1.

Bugfixes added:

• Fixed a seccomp failure in FIPS mode when SSL was enabled. [bsc#1052900]
• allow stat() to be called, which is required during SSL initialization by RAND_load_file().
• allow wait4() to be called so that the broker can wait for its child processes. [bsc#1021387]
• Revert the 'ssl_tlsv1_X'-style config file options back to their original spelling. The changes that dropped the underscore from the version numbers in release 3.0.4 breaks existing configurations and it was never documented anywhere -- not in the package's changelog and not in the packages's own man page.
• vsftpd follows the system-wide TLS cipher policy 'DEFAULT_SUSE' by default. Run the command 'openssl ciphers -v DEFAULT_SUSE' to see which ciphers this includes.
• allow sendto() syscall when /dev/log support is enabled. [bsc#786024]
• allow sendto() to be called from check_limits(), which is necessary for vsftpd to write to the system log.
• Added hardening to systemd service(s) (bsc#1181400).

Update to version 3.0.5:

• Fix ALPN callback to correctly select the 'ftp' string if present. Works with FileZilla-3.55.0.
• Fix a couple of seccomp policy issues with Fedora 34.

Update to version 3.0.4.

• Fix runtime SIGSYS crashes (seccomp sandbox policy tweaks).
• Reject HTTP verbs pre-login.
• Disable TLS prior to v1.2 by default.
• Close the control connection after 10 unknown commands pre-login.
• Reject any TLS ALPN advertisement that's not 'ftp'.
• Add ssl_sni_hostname option to require a match on incoming SNI hostname.
• The options 'ssl_tlsv1_1', 'ssl_tlsv1_2', and 'ssl_tlsv1_3' have been renamed to 'ssl_tlsv11', 'ssl_tlsv12', and 'ssl_tlsv13' respectively. Note that the man page has not been updated accordingly.

• OpenSSL was updated to version 1.1.1 in SLE-15-SP2, adding support for the TLSv1.3 protocol. As a consequence, some SLE-15 applications that link OpenSSL for TLS support -- like vsftpd --, gained the ability to use the newer TLS protocol, which created interoperability problems with FTP clients in some cases. To remedy the situation, '0001-Introduce-TLSv1.3-option.patch' was applied in a forked SLE-15-SP2 version of vsftpd. The patch adds the configuration option 'ssl_tlsv1_3' that system administrators can use to disable TLSv1.3 support on their servers. [bsc#1187188]

• allow getdents64 syscall in seccomp sandbox, fixes bsc#1179553

• Add pam_keyinit.so to PAM config file. [bsc#1144062]

• Fixed a segmentation fault that occurred while trying to write to an invalid TLS context. [bsc#1125951]

• Enable wait4(), sysinfo(), and shutdown() syscalls in seccomp sandbox. These are required for the daemon to work properly on SLE-15. [bsc#1089088, bsc#1180314]

• Add firewalld service file (bsc#1083705)

• Make sure to also require group nobody and user ftp bsc#1070653

• Fixed interoperability issue with various ftp clients that arose when vsftpd is configured with option 'use_localtime=YES'. Basically, it's fine to use local time stamps in directory listings, but responding to MDTM commands with any time zone other than UTC directly violates RFC3659 and leads FTP clients to misinterpret the file's time stamp. [bsc#1024961]

• Conditionally install xinetd service only on older releases

  • On current distributions we support the same functionality via systemd socket activation

• Fix build against OpenSSL 1.1. (bsc#1042673)

• Version bump to 3.0.3:

• Increase VSFTP_AS_LIMIT to 200MB; various reports.
• Make the PWD response more RFC compliant; report from Barry Kelly [email protected].
• Remove the trailing period from EPSV response to work around BT Internet issues; report from Tim Bishop [email protected].
• Fix syslog_enable issues vs. seccomp filtering. Report from Michal Vyskocil [email protected]. At least,…

This update for vsftpd fixes the following issues:

• CVE-2021-3618: Enforced security checks against ALPACA attack (bsc#1187678, bsc#1187686, PM-3322).

Bugfixes:

• Fixed a seccomp failure in FIPS mode when SSL was enabled (bsc#1052900).
• Allowed wait4() to be called so that the broker can wait for its child processes (bsc#1021387).
• Allowed sendto() syscall when /dev/log support is enabled (bsc#786024).

This update for vsftpd fixes the following issues:

• CVE-2021-3618: Enforced security checks against ALPACA attack (PM-3322, bsc#1187686, bsc#1187678).

Bugfixes:

• Fixed a seccomp failure in FIPS mode when SSL was enabled (bsc#1052900).
• Allowed wait4() to be called so that the broker can wait for its child processes (bsc#1021387).
• Allowed sendto() syscall when /dev/log support is enabled (bsc#786024).

This update for vsftpd fixes the following issues:

• CVE-2021-3618: Enforced security checks against ALPACA attack (PM-3322, jsc#SLE-23896, bsc#1187686, bsc#1187678).
• Added hardening to systemd services (bsc#1181400).

Bugfixes:

• Fixed a seccomp failure in FIPS mode when SSL was enabled (bsc#1052900).
• Allowed wait4() to be called so that the broker can wait for its child processes (bsc#1021387).
• Fixed hang when using seccomp and syslog (bsc#971784).
• Allowed sendto() syscall when /dev/log support is enabled (bsc#786024).

This update for vsftpd fixes the following issues:

• CVE-2021-3618: Enforced security checks against ALPACA attack (PM-3322, jsc#SLE-23895, bsc#1187686, bsc#1187678).
• Added hardening to systemd services (bsc#1181400).

Bugfixes:

• Fixed a seccomp failure in FIPS mode when SSL was enabled (bsc#1052900).
• Allowed wait4() to be called so that the broker can wait for its child processes (bsc#1021387).
• Fixed hang when using seccomp and syslog (bsc#971784).
• Allowed sendto() syscall when /dev/log support is enabled (bsc#786024).

This update for vsftpd fixes the following issues:

• CVE-2021-3618: Enforced security checks against ALPACA attack (PM-3322, bsc#1187686, bsc#1187678).

Bugfixes:

• Fixed a seccomp failure in FIPS mode when SSL was enabled (bsc#1052900).
• Allowed wait4() to be called so that the broker can wait for its child processes (bsc#1021387).
• Allowed sendto() syscall when /dev/log support is enabled (bsc#786024).

This update for nginx fixes the following issues:

• CVE-2021-3618: Fixed the ALPACA attack limiting the number of errors after which the connection is closed (bsc#1187685).

This update for nginx fixes the following issues:

• CVE-2021-3618: Fixed the ALPACA attack limiting the number of errors after which the connection is closed (bsc#1187685).

This update for nginx fixes the following issues:

• CVE-2021-3618: Fixed the ALPACA attack limiting the number of errors after which the connection is closed (bsc#1187685).

This update for nginx fixes the following issues:

• CVE-2021-3618: Fixed the ALPACA attack limiting the number of errors after which the connection is closed (bsc#1187685).

It was discovered that nginx Lua module mishandled certain inputs. An attacker could possibly use this issue to perform an HTTP Request Smuggling attack. This issue was fixed for Ubuntu 18.04 LTS and Ubuntu 20.04 LTS. (CVE-2020-11724)

It was discovered that nginx Lua module mishandled certain inputs. An attacker could possibly use this issue to disclose sensitive information. This issue only affects Ubuntu 18.04 LTS and Ubuntu 20.04 LTS. (CVE-2020-36309)

It was discovered that nginx mishandled the use of compatible certificates among multiple encryption protocols. If a remote attacker were able to intercept the communication, this issue could be used to redirect traffic between subdomains. (CVE-2021-3618)

USN-5371-1 fixed several vulnerabilities in nginx. This update provides the fix for CVE-2021-3618 for Ubuntu 22.04 LTS.

Original advisory details:

It was discovered that nginx Lua module mishandled certain inputs. An attacker could possibly use this issue to perform an HTTP Request Smuggling attack. This issue was fixed for Ubuntu 18.04 LTS and Ubuntu 20.04 LTS. (CVE-2020-11724)

It was discovered that nginx Lua module mishandled certain inputs. An attacker could possibly use this issue to disclose sensitive information. This issue only affects Ubuntu 18.04 LTS and Ubuntu 20.04 LTS. (CVE-2020-36309)

It was discovered that nginx mishandled the use of compatible certificates among multiple encryption protocols. If a remote attacker were able to intercept the communication, this issue could be used to redirect traffic between subdomains. (CVE-2021-3618)

It was discovered that vsftpd was vulnerable to the ALPACA TLS protocol content confusion attack. A remote attacker could possibly use this issue to redirect traffic from one subdomain to another.