sshd in OpenSSH before 7.3, when SHA256 or SHA512 are used for user password hashing, uses BLOWFISH hashing on a static password when the us
sshd in OpenSSH before 7.3, when SHA256 or SHA512 are used for user password hashing, uses BLOWFISH hashing on a static password when the username does not exist, which allows remote attackers to enumerate users by leveraging the timing difference between responses when a large password is provided.
Noroxi analysis
No Noroxi analysis for this record yet
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We use this product, ask for help- Published
- Feb 13, 2017
- Updated
- Jun 16, 2026
- EPSS
- 88.9% · 100th percentile
- CWE
- CWE-200
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Report tools
Action score
50
Plan
Add it to your regular patch cycle.
- CVSS
- 23 / 40 · 5.9 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 27 / 30 · 88.9%
CISA SSVC decision
- Exploitation
- proof of concept
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| openbsd | openssh | cpe:2.3:a:openbsd:openssh |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- openbsd opensshup to 7.2 inclusive
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Alpine:v3.2 | openssh | before 6.8_p1-r7 | 6.8_p1-r7 |
| Alpine:v3.3 | openssh | before 7.2_p2-r1 | 7.2_p2-r1 |
| Debian:12 | openssh | before 1:7.2p2-6 | 1:7.2p2-6 |
| Debian:7 | openssh | before 1:6.0p1-4+deb7u5 | 1:6.0p1-4+deb7u5 |
| Debian:8 | openssh | before 1:6.7p1-5+deb8u3 | 1:6.7p1-5+deb8u3 |
| openSUSE:Tumbleweed | openssh | before 7.2p2-3.1 | 7.2p2-3.1 |
| Red Hat:enterprise_linux:6::client | openssh | before 0:5.3p1-123.el6_9 | 0:5.3p1-123.el6_9 |
| Red Hat:enterprise_linux:6::client | openssh-askpass | before 0:5.3p1-123.el6_9 | 0:5.3p1-123.el6_9 |
| Red Hat:enterprise_linux:6::client | openssh-clients | before 0:5.3p1-123.el6_9 | 0:5.3p1-123.el6_9 |
| Red Hat:enterprise_linux:6::client | openssh-debuginfo | before 0:5.3p1-123.el6_9 | 0:5.3p1-123.el6_9 |
| Red Hat:enterprise_linux:6::client | openssh-ldap | before 0:5.3p1-123.el6_9 | 0:5.3p1-123.el6_9 |
| Red Hat:enterprise_linux:6::client | openssh-server | before 0:5.3p1-123.el6_9 | 0:5.3p1-123.el6_9 |
| Red Hat:enterprise_linux:6::client | pam_ssh_agent_auth | before 0:0.9.3-123.el6_9 | 0:0.9.3-123.el6_9 |
| Red Hat:enterprise_linux:7::client | openssh | before 0:7.4p1-11.el7 | 0:7.4p1-11.el7 |
| Red Hat:enterprise_linux:7::client | openssh-askpass | before 0:7.4p1-11.el7 | 0:7.4p1-11.el7 |
| Red Hat:enterprise_linux:7::client | openssh-cavs | before 0:7.4p1-11.el7 | 0:7.4p1-11.el7 |
| Red Hat:enterprise_linux:7::client | openssh-clients | before 0:7.4p1-11.el7 | 0:7.4p1-11.el7 |
| Red Hat:enterprise_linux:7::client | openssh-debuginfo | before 0:7.4p1-11.el7 | 0:7.4p1-11.el7 |
| Red Hat:enterprise_linux:7::client | openssh-keycat | before 0:7.4p1-11.el7 | 0:7.4p1-11.el7 |
| Red Hat:enterprise_linux:7::client | openssh-ldap | before 0:7.4p1-11.el7 | 0:7.4p1-11.el7 |
| Red Hat:enterprise_linux:7::client | openssh-server | before 0:7.4p1-11.el7 | 0:7.4p1-11.el7 |
| Red Hat:enterprise_linux:7::client | openssh-server-sysvinit | before 0:7.4p1-11.el7 | 0:7.4p1-11.el7 |
| Red Hat:enterprise_linux:7::client | pam_ssh_agent_auth | before 0:0.10.3-1.11.el7 | 0:0.10.3-1.11.el7 |
| SUSE:Linux Enterprise Desktop 12 SP1 | openssh | before 6.6p1-52.1 | 6.6p1-52.1 |
+6
Same product
openbsd: all recordsOther highest-scoring records for the same primary product.
- CVE-2023-38408The PKCS#11 feature in ssh-agent in OpenSSH before 9.3p2 has an insufficiently trustworthy search path, leading to remote code execution if 63This week
- CVE-2023-25136OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during options.kex_algorithms handling.53Plan
- CVE-2018-15473OpenSSH through 7.7 is prone to a user enumeration vulnerability due to not delaying bailout for an invalid authenticating user until after 51Plan
- CVE-2016-6515The auth_password function in auth-passwd.c in sshd in OpenSSH before 7.3 does not limit password lengths for password authentication, which48Plan
- CVE-2002-0640Buffer overflow in sshd in OpenSSH 2.3.1 through 3.3 may allow remote attackers to execute arbitrary code via a large number of responses du48Plan
- CVE-2006-5051Signal handler race condition in OpenSSH before 4.4 allows remote attackers to cause a denial of service (crash), and possibly execute arbit45Plan
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| alpine:openssh | 6.8_p1-r7 · Alpine:v3.2 | Package registry (OSV) |
| debian:openssh | 1:7.2p2-6 · Debian:12 | Package registry (OSV) |
| opensuse:openssh | 7.2p2-3.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| red hat:openssh | 0:7.4p1-11.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:openssh-askpass | 0:7.4p1-11.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:openssh-cavs | 0:7.4p1-11.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:openssh-clients | 0:7.4p1-11.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:openssh-debuginfo | 0:7.4p1-11.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:openssh-keycat | 0:7.4p1-11.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:openssh-ldap | 0:7.4p1-11.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:openssh-server | 0:7.4p1-11.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:openssh-server-sysvinit | 0:7.4p1-11.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:pam_ssh_agent_auth | 0:0.10.3-1.11.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| suse:openssh | 6.6p1-52.1 · SUSE:Linux Enterprise Desktop 12 SP1 | Package registry (OSV) |
| suse:openssh-askpass-gnome | 6.6p1-52.1 · SUSE:Linux Enterprise Desktop 12 SP1 | Package registry (OSV) |
| suse:openssh-openssl1 | 6.6p1-15.1 · SUSE:Linux Enterprise Server 11-SECURITY | Package registry (OSV) |
Exploit status
Weaponized
A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.
Evidence
- Metasploit module ×1
- Exploit-DB entry ×2
- Nuclei detection template ×2
- Proof-of-concept repository on GitHub ×7
Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.
| Source | Kind | Date |
|---|---|---|
| Exploit-DB entry | remote | 2016-07-20 |
| Exploit-DB entry | remote | 2016-07-18 |
| Metasploit module | auxiliary/scanner/ssh/ssh_enumusersSSH Username Enumerationauxiliary | — |
| Nuclei detection template | Nuclei template mikrotik-ssh-detect | — |
| Nuclei detection template | Nuclei template openssh-detect | — |
| Proof-of-concept repository on GitHub | stars:3 | 2019-08-25 |
| Proof-of-concept repository on GitHub | stars:1 | 2023-03-19 |
| Proof-of-concept repository on GitHub | stars:0 | 2023-09-01 |
| Proof-of-concept repository on GitHub | stars:1 | 2025-03-14 |
| Proof-of-concept repository on GitHub | stars:0 | 2025-04-12 |
| Proof-of-concept repository on GitHub | stars:0 | 2025-07-17 |
| Proof-of-concept repository on GitHub | stars:0 | 2026-04-30 |
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
- First PoC-211 d
- Published
- TodaySep 30, 2026+3516 d
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- Special conditions such as timing or configuration are required.
If successful
- Confidentiality
- high · data can be read
- Integrity
- none
- Availability
- none
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- None
- Availability impact
- None
Weakness class (CWE)
CWE-200 · Exposure of Sensitive Information to an Unauthorized ActorCVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
nvd-secondary
Root cause
The extension requests broader permissions than its function needs and sends the data it collects out for purposes beyond its stated function.
The bug in code
The whole CWE-200 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
{ "permissions": ["tabs", "<all_urls>"], "background": { "service_worker": "analytics.js" }}Fixed
{ "permissions": ["activeTab"], "host_permissions": ["https://yildiz.example/*"]}Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- ExcavationCAPEC-116likelihood: High · Medium
- Subverting Environment Variable ValuesCAPEC-13likelihood: High · Very High
- FootprintingCAPEC-169likelihood: High · Very Low
- Exploiting Trust in ClientCAPEC-22likelihood: High · High
- FingerprintingCAPEC-224likelihood: High · Very Low
- ICMP Echo Request PingCAPEC-285likelihood: Medium · Low
- TCP SYN ScanCAPEC-287Low
- Enumerate Mail Exchange (MX) RecordsCAPEC-290Low
ATT&CK techniques
- System Service DiscoveryT1007
- System Network Configuration DiscoveryT1016
- Remote System DiscoveryT1018
- System Owner/User DiscoveryT1033
- Masquerading: Match Legitimate Name or LocationT1036.005
- Network Service ScanningT1046
- System Network Connections DiscoveryT1049
- Process DiscoveryT1057
- Permission Groups DiscoveryT1069
- System Information DiscoveryT1082
- File and Directory DiscoveryT1083
- Account DiscoveryT1087
- Multi-Factor Authentication InterceptionT1111
- Peripheral Device DiscoveryT1120
- System Time DiscoveryT1124
- Access Token Manipulation:Token Impersonation/TheftT1134.001
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- seclists.org/fulldisclosure/2016/Jul/51
- www.debian.org/security/2016/dsa-3626
- www.securityfocus.com/bid/91812
- www.securitytracker.com/id/1036319
- access.redhat.com/errata/RHSA-2017:2029
- access.redhat.com/errata/RHSA-2017:2563
- cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf
- security.gentoo.org/glsa/201612-18
- security.netapp.com/advisory/ntap-20190206-0001/
- www.exploit-db.com/exploits/40113/
- www.exploit-db.com/exploits/40136/
- www.openssh.com/txt/release-7.3
Vendor advisories and official records. Exploit/PoC links are deliberately left out.