ssl3_get_record in s3_pkt.c for OpenSSL before 0.9.7a and 0.9.6 before 0.9.6i does not perform a MAC computation if an incorrect block cipher padding is used, which causes an information leak (timing discrepancy) that may make it easier to launch cryptographic attacks that rely on distinguishing between padding and MAC verification errors, possibly leading to extraction of the original plaintext, aka the "Vaudenay timing attack."

OpenSSH-portable (OpenSSH) 3.6.1p1 and earlier with PAM support enabled immediately sends an error message when a user does not exist, which allows remote attackers to determine valid usernames via a timing attack.

OpenSSH 4.6 and earlier, when ChallengeResponseAuthentication is enabled, allows remote attackers to determine the existence of user accounts by attempting to authenticate via S/KEY, which displays a different response if the user account exists, a similar issue to CVE-2001-1483.

sshd in OpenSSH before 4.2, when GSSAPIDelegateCredentials is enabled, allows GSSAPI credentials to be delegated to clients who log in using non-GSSAPI methods, which could cause those credentials to be exposed to untrusted users or hosts.

Unspecified vulnerability in portable OpenSSH before 4.4, when running on some platforms, allows remote attackers to determine the validity of usernames via unknown vectors involving a GSSAPI "authentication abort."

isakmpd in OpenBSD 3.8, 3.9, and possibly earlier versions, creates Security Associations (SA) with a replay window of size 0 when isakmpd acts as a responder during SA negotiation, which allows remote attackers to replay IPSec packets and bypass the replay protection.

Remotely observable behaviour in auth-gss2.c in OpenSSH through 7.8 could be used by remote attackers to detect existence of users on a target system when GSS2 is in use. NOTE: the discoverer states 'We understand that the OpenSSH developers do not want to treat such a username enumeration (or "oracle") as a vulnerability.'

OpenSSH through 7.7 is prone to a user enumeration vulnerability due to not delaying bailout for an invalid authenticating user until after the packet containing the request has been fully parsed, related to auth2-gss.c, auth2-hostbased.c, and auth2-pubkey.c.

The key_certify function in usr.bin/ssh/key.c in OpenSSH 5.6 and 5.7, when generating legacy certificates using the -t command-line option in ssh-keygen, does not initialize the nonce field, which might allow remote attackers to obtain sensitive stack memory contents or make it easier to conduct hash collision attacks.

The TCP implementation in various BSD operating systems (tcp_input.c) does not properly block connections to broadcast addresses, which could allow remote attackers to bypass intended filters via packets with a unicast link layer address and an IP broadcast address.

The "echo simulation" traffic analysis countermeasure in OpenSSH before 2.9.9p2 sends an additional echo packet after the password and carriage return is entered, which could allow remote attackers to determine that the countermeasure is being used.

A kernel leak in the OpenBSD kernel allows IPsec packets to be sent unencrypted.

rpc.mountd on Linux, Ultrix, and possibly other operating systems, allows remote attackers to determine the existence of a file on the server by attempting to mount that file, which generates different error messages depending on whether the file exists or not.

The system configuration control (sysctl) facility in BSD based operating systems OpenBSD 2.2 and earlier, and FreeBSD 2.2.5 and earlier, does not properly restrict source routed packets even when the (1) dosourceroute or (2) forwarding variables are set, which allows remote attackers to spoof TCP connections.

OpenSSH through 8.7 allows remote attackers, who have a suspicion that a certain combination of username and public key is known to an SSH server, to test whether this suspicion is correct. This occurs because a challenge is sent only when that combination could be valid for a login session. NOTE: the vendor does not recognize user enumeration as a vulnerability for this product

The client side in OpenSSH 5.7 through 8.4 has an Observable Discrepancy leading to an information leak in the algorithm negotiation. This allows man-in-the-middle attackers to target initial connection attempts (where no host key for the server has been cached by the client). NOTE: some reports state that 8.5 and 8.6 are also affected.

In Jenkins 2.355 and earlier, LTS 2.332.3 and earlier, an observable timing discrepancy on the login form allows distinguishing between login attempts with an invalid username, and login attempts with a valid username and wrong password, when using the Jenkins user database security realm.

Redmine before 4.0.9 and 4.1.x before 4.1.3 allows an attacker to learn the values of internal authentication keys by observing timing differences in string comparison operations within SysController and MailHandlerController.

IBM Security Identity Manager 7.0.2 could allow a remote user to enumerate usernames due to a difference of responses from valid and invalid login attempts. IBM X-Force ID: 200018

CA Technologies Identity Governance 12.6, 14.0, 14.1, and 14.2 and CA Identity Suite Virtual Appliance 14.0, 14.1, and 14.2 provide telling error messages that may allow remote attackers to enumerate account names.

In Directus 8.x through 8.8.1, an attacker can discover whether a user is present in the database through the password reset feature. NOTE: This vulnerability only affects products that are no longer supported by the maintainer

mailboxd in Zimbra Collaboration Suite 8.8 before 8.8.8; 8.7 before 8.7.11.Patch3; and 8.6 allows Account Enumeration by leveraging a Discrepancy between the "HTTP 404 - account is not active" and "HTTP 401 - must authenticate" errors.

A vulnerability in the RADIUS authentication module of Cisco Policy Suite could allow an unauthenticated, remote attacker to determine whether a subscriber username is valid. The vulnerability occurs because the Cisco Policy Suite RADIUS server component returns different authentication failure messages based on the validity of usernames. An attacker could use these messages to determine whether a valid subscriber username has been identified. The attacker could use this information in subsequent attacks against the system. Cisco Bug IDs: CSCvg47830.

A vulnerability has been identified in Desigo DXR2 (All versions < V01.21.142.5-22), Desigo PXC3 (All versions < V01.21.142.4-18), Desigo PXC4 (All versions < V02.20.142.10-10884), Desigo PXC5 (All versions < V02.20.142.10-10884). The login functionality of the application fails to normalize the response times of login attempts performed with wrong usernames with the ones executed with correct usernames. A remote unauthenticated attacker could exploit this side-channel information to perform a username enumeration attack and identify valid usernames.

Jenkins Configuration as Code Plugin 1.55 and earlier used a non-constant time comparison function when validating an authentication token allowing attackers to use statistical methods to obtain a valid authentication token.

In NocoDB, versions 0.9 to 0.83.8 are vulnerable to Observable Discrepancy in the password-reset feature. When requesting a password reset for a given email address, the application displays an error message when the email isn't registered within the system. This allows attackers to enumerate the registered users' email addresses.

Flask-AppBuilder is an application development framework, built on top of the Flask web framework. In affected versions there exists a user enumeration vulnerability. This vulnerability allows for a non authenticated user to enumerate existing accounts by timing the response time from the server when you are logging in. Users are advised to upgrade to version 3.4.4 as soon as possible. There are no known workarounds for this issue.

WatchGuard Fireware allows user enumeration, e.g., in the Firebox XML-RPC login handler. A login request that contains a blank password sent to the XML-RPC agent in Fireware v11.12.1 and earlier returns different responses for valid and invalid usernames. An attacker could exploit this vulnerability to enumerate valid usernames on an affected Firebox.

A vulnerability in Cisco Unified Communications Manager (Unified CM), Cisco Unified Communications Manager Session Management Edition (Unified CM SME), and Cisco Unity Connection could allow an unauthenticated, remote attacker to perform a timing attack. This vulnerability is due to insufficient protection of a system password. An attacker could exploit this vulnerability by observing the time it takes the system to respond to various queries. A successful exploit could allow the attacker to determine a sensitive system password.

The NPSVG3.dll ActiveX control for Adobe SVG Viewer 3.02 and earlier, when running on Internet Explorer, allows remote attackers to determine the existence of arbitrary files by setting the src property to the target filename and using Javascript to determine if the web page immediately stops loading, which indicates whether the file exists or not.

The web mail service in Woppoware PostMaster 4.2.2 (build 3.2.5) generates different error messages depending on whether a user exists or not, which allows remote attackers to determine valid usernames.

Jetty through 9.4.x is prone to a timing channel in util/security/Password.java, which makes it easier for remote attackers to obtain access by observing elapsed times before rejection of incorrect passwords.

ProFTPD 1.2.x, including 1.2.8 and 1.2.10, responds in a different amount of time when a given username exists, which allows remote attackers to identify valid usernames by timing the server response.

The firewall in Astaro Security Linux before 4.024 sends responses to SYN-FIN packets, which makes it easier for remote attackers to obtain information about the system and construct specialized attacks.

Nettica Corporation INTELLIPEER Email Server 1.01 displays different error messages for valid and invalid account names, which allows remote attackers to determine valid account names.

Thinfinity VirtualUI before 3.0 allows a malicious actor to enumerate users registered in the OS (Windows) through the /changePassword URI. By accessing the vector, an attacker can determine if a username exists thanks to the message returned; it can be presented in different languages according to the configuration of VirtualUI. Common users are administrator, admin, guest and krgtbt.

In Cibele Thinfinity VirtualUI before 3.0, /changePassword returns different responses for invalid authentication requests depending on whether the username exists.

Dalmark Systems Systeam 2.22.8 build 1724 is vulnerable to User enumeration. The Systeam application is an ERP system that uses a mixed architecture based on SaaS tenant and user management, and on-premise database and web application counterparts. This issue occurs during the identification of the correct tenant for a given user, where a difference in messages could allow an attacker to determine if the given user is valid or not, enabling a brute force attack with valid users.

CVS 1.11.x before 1.11.17, and 1.12.x before 1.12.9, allows remote attackers to determine the existence of arbitrary files and directories via the -X command for an alternate history file, which causes different error messages to be returned.

AIX 4.3.3 through AIX 5.1, when direct remote login is disabled, displays a different message if the password is correct, which allows remote attackers to guess the password via brute force methods.

YaBB 1 SP 1.3.1 displays different error messages when a user exists or not, which makes it easier for remote attackers to identify valid users and conduct a brute force password guessing attack.

ManageEngine ADSelfService Plus below build 6116 contains an observable response discrepancy in the UMCP operation of the ChangePasswordAPI. This allows an unauthenticated remote attacker to determine whether a Windows domain user exists.

Novell iChain 2.2 before Support Pack 1 uses a shorter timeout for a non-existent user than a valid user, which makes it easier for remote attackers to guess usernames and conduct brute force password guessing.

Joe Testa hellbent 01 allows remote attackers to determine the full path of the web root directory via a GET request with a relative path that includes the root's parent, which generates a 403 error message if the parent is incorrect, but a normal response if the parent is correct.

An exposure of sensitive information vulnerability exists in TCExam <= 14.8.1. If a password reset request was made for an email address that was not registered with a user then we would be presented with an ‘unknown email’ error. If an email is given that is registered with a user then this error will not appear. A malicious actor could abuse this to enumerate the email addresses of

IPFilter 3.4.25 and earlier sets a different TTL when a port is being filtered than when it is not being filtered, which allows remote attackers to identify filtered ports by comparing TTLs.

PGP Security PGPfire 7.1 for Windows alters the system's TCP/IP stack and modifies packets in ICMP error messages in a way that allows remote attackers to determine that the system is running PGPfire.

One-Time Passwords In Everything (a.k.a OPIE) 2.32 and 2.4 allows remote attackers to determine the existence of user accounts by printing random passphrases if the user account does not exist and static passphrases if the user account does exist.

AmTote International homebet program returns different error messages when invalid account numbers and PIN codes are provided, which allows remote attackers to determine the existence of valid account numbers via a brute force attack.

The Extended Control List (ECL) feature of the Java Virtual Machine (JVM) in Lotus Notes Client R5 allows malicious web site operators to determine the existence of files on the client by measuring delays in the execution of the getSystemResource method.