In Enterprise Networking Operating System (ENOS) in Lenovo and IBM RackSwitch and BladeCenter products, an authentication bypass known as "H
In Enterprise Networking Operating System (ENOS) in Lenovo and IBM RackSwitch and BladeCenter products, an authentication bypass known as "HP Backdoor" was discovered during a Lenovo security audit in the serial console, Telnet, SSH, and Web interfaces. This bypass mechanism can be accessed when performing local authentication under specific circumstances. If exploited, admin-level access to the switch is granted.
- Published
- Jan 10, 2018
- Updated
- Jun 16, 2026
- EPSS
- 0.3% · 17th percentile
- CWE
- CWE-287
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Report tools
Action score
28
Monitor
Low priority for now.
- CVSS
- 28 / 40 · 7.0 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.3%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| lenovo | enterprise network operating system | cpe:2.3:o:lenovo:enterprise_network_operating_system |
| lenovo | flex system fabric cn4093 10gb converged scalable switch | cpe:2.3:h:lenovo:flex_system_fabric_cn4093_10gb_converged_scalable_switch |
| lenovo | flex system fabric en4093r 10gb scalable switch | cpe:2.3:h:lenovo:flex_system_fabric_en4093r_10gb_scalable_switch |
| lenovo | flex system fabric si4093 10gb system interconnect module | cpe:2.3:h:lenovo:flex_system_fabric_si4093_10gb_system_interconnect_module |
| lenovo | flex system si4091 system interconnect module | cpe:2.3:h:lenovo:flex_system_si4091_system_interconnect_module |
| lenovo | rackswitch g7028 | cpe:2.3:h:lenovo:rackswitch_g7028 |
| lenovo | rackswitch g7052 | cpe:2.3:h:lenovo:rackswitch_g7052 |
| lenovo | rackswitch g8052 | cpe:2.3:h:lenovo:rackswitch_g8052 |
| lenovo | rackswitch g8124e | cpe:2.3:h:lenovo:rackswitch_g8124e |
| lenovo | rackswitch g8264 | cpe:2.3:h:lenovo:rackswitch_g8264 |
| lenovo | rackswitch g8264cs | cpe:2.3:h:lenovo:rackswitch_g8264cs |
| lenovo | rackswitch g8272 | cpe:2.3:h:lenovo:rackswitch_g8272 |
and 18 more
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- lenovo enterprise network operating systembefore 8.4.6.0
Versions reported by the vendor
Affected version ranges reported by the assigning authority (lenovo). Independent of NVD's CPE analysis and usually ahead of it.
Lenovo Group Ltd. Enterprise Network Operating System affecting Lenovo and IBM RackSwitch and BladeCenter Products
- Earlier thanaffected
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
No fix version is recorded for this entry. Check the references for vendor advisories.
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
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.
No dated events beyond publication.
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
The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.
Technical details
Attack conditions
- Someone with local access to the system can trigger it.
- A low-privileged account is enough.
- No user action is required.
- Special conditions such as timing or configuration are required.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Local
- Attack complexity
- High
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-287 · Improper AuthenticationCVSS vector
CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
nvd-primary
Root cause
Authentication is added route by route instead of being enforced in one place. When a route added later bypasses the shared middleware, the session check never runs for it.
The bug in code
The whole CWE-287 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
app.use("/admin", requireSession, adminRouter);
// Route added later skips the middlewareapp.post("/admin-api/config", updateConfig);Fixed
const admin = express.Router();admin.use(requireSession, requireRole("admin"));
admin.post("/config", updateConfig);app.use("/admin", admin);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)
- Authentication AbuseCAPEC-114Medium
- Authentication BypassCAPEC-115Medium
- Identity SpoofingCAPEC-151likelihood: Medium · Medium
- Fake the Source of DataCAPEC-194Medium
- Exploiting Trust in ClientCAPEC-22likelihood: High · High
- Utilizing REST's Trust in the System Resource to Obtain Sensitive DataCAPEC-57likelihood: Medium · Very High
- Session HijackingCAPEC-593likelihood: High · Very High
- Token ImpersonationCAPEC-633Medium
ATT&CK techniques
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
Vendor advisories and official records. Exploit/PoC links are deliberately left out.