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.

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.

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.

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.

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

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 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.

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 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.

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.

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.

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 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 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.

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.

ArGoSoft FTP before 1.4.2.1 generates an error message if the user name does not exist instead of prompting for a password, which allows remote attackers to determine valid usernames.

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.

CMAC verification functionality in Microchip Atmel ATSAMA5 products is vulnerable to vulnerable to timing and power analysis attacks.

Proxmox VE prior to 3.2: 'AccessControl.pm' User Enumeration Vulnerability

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.

wolfSSL 4.3.0 has mulmod code in wc_ecc_mulmod_ex in ecc.c that does not properly resist timing side-channel attacks.

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.

Fixed in v1.5.1, Argo version v1.5.0 was vulnerable to a user-enumeration vulnerability which allowed attackers to determine the usernames of valid (non-SSO) accounts because /api/v1/session returned 401 for an existing username and 404 otherwise.

The private-key operations in ecc.c in wolfSSL before 4.4.0 do not use a constant-time modular inverse when mapping to affine coordinates, aka a "projective coordinates leak."

Citrix ShareFile before 19.12 allows User Enumeration. It is possible to enumerate application username based on different server responses using the request to check the otp code. No authentication is required.

In BIG-IP 15.0.0, 14.1.0-14.1.0.6, 14.0.0-14.0.0.5, 13.0.0-13.1.1.5, 12.1.0-12.1.4.1, 11.5.1-11.6.4, BIG-IQ 7.0.0, 6.0.0-6.1.0,5.2.0-5.4.0, iWorkflow 2.3.0, and Enterprise Manager 3.1.1, the Configuration utility login page may not follow best security practices when handling a malicious request.

In BIG-IP 11.5.1-11.5.8 and 11.6.1-11.6.3, the Configuration Utility login page may not follow best security practices when handling a malicious request.

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.

IBM Guardium Data Encryption (GDE) 5.0.0.2 behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor, which could facilitate username enumeration. IBM X-Force ID: 213856.

RSA BSAFE Crypto-C Micro Edition versions prior to 4.1.4 and RSA Micro Edition Suite versions prior to 4.4 are vulnerable to an Information Exposure Through Timing Discrepancy. A malicious remote user could potentially exploit this vulnerability to extract information leaving data at risk of exposure.

RSA BSAFE Crypto-C Micro Edition, versions prior to 4.0.5.3 (in 4.0.x) and versions prior to 4.1.3.3 (in 4.1.x), and RSA Micro Edition Suite, versions prior to 4.0.11 (in 4.0.x) versions prior to 4.1.6.1 (in 4.1.x) and versions prior to 4.3.3 (4.2.x and 4.3.x) are vulnerable to an Information Exposure Through Timing Discrepancy. A malicious remote user could potentially exploit this vulnerability to extract information leaving data at risk of exposure.

Pimcore is an open source data & experience management platform. In versions prior to 10.1.3, it is possible to enumerate usernames via the forgot password functionality. This issue is fixed in version 10.1.3. As a workaround, one may apply the available patch manually.

TrevorC2 v1.1/v1.2 fails to prevent fingerprinting primarily via a discrepancy between response headers when responding to different HTTP methods, also via predictible responses when accessing and interacting with the "SITE_PATH_QUERY".

An issue was discovered in Symfony 4.2.0 to 4.2.11 and 4.3.0 to 4.3.7. The ability to enumerate users was possible due to different handling depending on whether the user existed when making unauthorized attempts to use the switch users functionality. This is related to symfony/security.

The Reset Password feature in Pagekit 1.0.17 gives a different response depending on whether the e-mail address of a valid user account is entered, which might make it easier for attackers to enumerate accounts.

An issue was discovered in ConnectWise Control (formerly known as ScreenConnect) 19.3.25270.7185. There is a user enumeration vulnerability, allowing an unauthenticated attacker to determine with certainty if an account exists for a given username.

Dropbear 2011.54 through 2018.76 has an inconsistent failure delay that may lead to revealing valid usernames, a different issue than CVE-2018-15599.

In CentOS-WebPanel.com (aka CWP) CentOS Web Panel 0.9.8.846, the Login process allows attackers to check whether a username is valid by reading the HTTP response.

CyberArk Identity 21.5.131, when handling an invalid authentication attempt, sometimes reveals whether the username is valid. In certain authentication policy configurations with MFA, the API response length can be used to differentiate between a valid user and an invalid one (aka Username Enumeration). Response differentiation enables attackers to enumerate usernames of valid application users. Attackers can use this information to leverage brute-force and dictionary attacks in order to discover valid account information such as passwords.

An Information Exposure issue (issue 2 of 2) was discovered in GitLab Community and Enterprise Edition before 11.7.8, 11.8.x before 11.8.4, and 11.9.x before 11.9.2. During the OAuth authentication process, the application attempts to validate a parameter in an insecure way, potentially exposing data.

In mymbCONNECT24, mbCONNECT24 <= 2.9.0 an unauthenticated user can enumerate valid backend users by checking what kind of response the server sends for crafted invalid login attempts.

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

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

In Bromite through 78.0.3904.130, there are adblock rules in the release APK; therefore, probing which resources are blocked and which aren't can identify the application version and defeat the User-Agent protection mechanism.