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CVE Record

CVE-2018-0732: Client DoS due to large DH parameter

During key agreement in a TLS handshake using a DH(E) based ciphersuite a malicious server can send a very large prime value to the client. This will cause the client to spend an unreasonably long period of time generating a key for this prime resulting in a hang until the client has finished. This could be exploited in a Denial Of Service attack. Fixed in OpenSSL 1.1.0i-dev (Affected 1.1.0-1.1.0h). Fixed in OpenSSL 1.0.2p-dev (Affected 1.0.2-1.0.2o).

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

A malicious TLS server could make vulnerable OpenSSL clients hang during connection setup by forcing expensive Diffie-Hellman key processing. This is a denial-of-service issue against clients, not evidence of data theft or code execution.

Executive priority

Treat this as a targeted availability risk for vulnerable clients rather than a broad compromise event. Patch during normal security maintenance, faster for systems that connect to untrusted TLS endpoints.

Technical view

OpenSSL clients using DH(E)-based TLS ciphersuites could spend an unreasonable time generating a key when a malicious server supplies a very large prime during handshake. The bundle identifies OpenSSL 1.1.0 through 1.1.0h and 1.0.2 through 1.0.2o as affected, with fixes in 1.1.0i-dev and 1.0.2p-dev.

Likely exposure

Exposure is most relevant for systems, applications, agents, or appliances that act as TLS clients using affected OpenSSL versions and can connect to untrusted or attacker-controlled servers.

Exploitation context

The source bundle describes denial-of-service potential by a malicious server during TLS negotiation. It does not show CISA KEV listing or cited evidence of active exploitation.

Researcher notes

Evidence supports a client-side OpenSSL denial-of-service condition tied to DH(E) ciphersuites and oversized DH parameters. The bundle lacks CVSS, CWE, exploit maturity detail, and product-specific impact beyond OpenSSL and downstream advisories.

Mitigation direction

  • Upgrade OpenSSL to a fixed upstream or vendor-supported patched package.
  • Use Debian, Red Hat, Ubuntu, Gentoo, or relevant vendor advisories for package-specific remediation.
  • Prioritize clients that connect to untrusted external TLS services.
  • Check vendor guidance for embedded products or bundled OpenSSL copies.

Validation and detection

  • Inventory OpenSSL versions in operating systems, containers, agents, and appliances.
  • Confirm affected ranges: 1.1.0-1.1.0h and 1.0.2-1.0.2o.
  • Map distribution packages to the listed vendor advisories.
  • Verify patched versions are deployed on TLS client workloads.
Prepared
Confidence
high
Sources
8

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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CVE-2018-0732 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
35Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
OpenSSLOpenSSLFixed in OpenSSL 1.1.0i-dev (Affected 1.1.0-1.1.0h), Fixed in OpenSSL 1.0.2p-dev (Affected 1.0.2-1.0.2o)Listed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.