CVE-2015-1637: Affected product: security vulnerability

Recommended actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available

What, why and how

Schannel (aka Secure Channel) in Microsoft Windows Server 2003 SP2, Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8, Windows 8.1, Windows Server 2012 Gold and R2, and Windows RT Gold and 8.1 does not properly restrict TLS state transitions, which makes it easier for remote attackers to conduct cipher-downgrade attacks to EXPORT_RSA ciphers via crafted TLS traffic, related to the "FREAK" issue, a different vulnerability than CVE-2015-0204 and CVE-2015-1067.

What

Why

The current structured CVE record identifies a security weakness, but the root cause requires confirmation in the linked vendor material.

How

An attacker operating through the affected interface may attempt exploitation when the stated preconditions are met. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

Why

The current structured CVE record identifies a security weakness, but the root cause requires confirmation in the linked vendor material.

How

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation

Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.

No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material

Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.

None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path: the affected interface → vulnerable operation → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface: Unspecified
Privileges required: None: unauthenticated exploitation is possible
User interaction: Not stated in the selected CVSS metric
Attack complexity: Not stated in the selected CVSS metric
Security boundary: Not stated in the selected CVSS metric
Weakness ? CWE means Common Weakness Enumeration: a standard category for the underlying weakness.: CWE-310 ↗
CWE-310. Open the MITRE definition for the exact weakness description.
CVSS vector ? CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.: AV:N/AC:M/Au:N/C:N/I:P/A:N
Post-exploitation / living off the land: No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.

UnauthenticatedCWE-310

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2015-1767Official EUVD mapping

0 linked advisory records.

Official EUVD record ↗

JVN iPedia · Japanese · JVNDB-2015-001770複数の Apple 製品の Secure Transport における EXPORT_RSA 暗号に対して暗号スイートのダウングレード攻撃を実行される脆弱性

複数の Apple 製品の Secure Transport は、TLS ステートの遷移を適切に制限しないため、EXPORT_RSA 暗号に対して暗号スイートのダウングレード攻撃を実行される脆弱性が存在します。本件は、"FREAK" 問題に関する脆弱性です。本脆弱性は、CVE-2015-0204 および CVE-2015-1637 とは異なる脆弱性です。

Official advisory ↗

JVN iPedia · Japanese · JVNDB-2015-001665複数の Microsoft Windows 製品の Schannel における EXPORT_RSA 暗号に対して暗号スイートのダウングレード攻撃を実行される脆弱性

複数の Microsoft Windows 製品の Schannel (別名 Secure Channel) は、TLS ステートの遷移を適切に制限しないため、EXPORT_RSA 暗号に対して暗号スイートのダウングレード攻撃を実行される脆弱性が存在します。本件は、"FREAK" 問題に関する脆弱性です。マイクロソフトセキュリティ情報には、この脆弱性は「Schannel のセキュリティ機能のバイパスの脆弱性」と記載されています。

Official advisory ↗

JVN iPedia · Japanese · JVNDB-2015-001671** 削除 ** Apple iOS の Secure Transport における EXPORT_RSA 暗号に対して暗号スイートのダウングレード攻撃を実行される脆弱性

** 削除 ** 本案件は、CVE-2015-1067 の内容と重複していることが判明したため削除されました。CVE-2015-1067 を参照してください。 Apple iOS の Secure Transport は、TLS ステートの遷移を適切に制限しないため、EXPORT_RSA 暗号に対して暗号スイートのダウングレード攻撃を実行される脆弱性が存在します。本件は、"FREAK" 問題に関する脆弱性です。本脆弱性は、CVE-2015-0204 および CVE-2015-1637 とは異なる脆弱性です。

Official advisory ↗

KISA KrCERT/CC · Korean · KNVD-4505원격코드실행 취약점 등 MS 보안업데이트 14종

0] 원격 데스크톱 프로토콜의 취약점으로 인한 서비스 거부 문제 ##### □ 영향 공격자가 영향 받는 시스템의 서비스 거부를 유발 ##### □ 설명 공격자가 메모리의 개체를 제대로 해제하지 못하는 원격 데스크톱 프로토콜 세션을 만드는 경우, 서비스 거부가 발생할 수 있는 취약점이 존재 관련취약점 : - 원격 데스크톱 프로토콜 서비스 거부 취약점 ? (CVE-2015-0079) 영향 : 서비스 거부 중요도 : 중요 ##### □ 해당시스템 참조사이트 참고 - 한글 : https://technet.microsoft.com/ko-kr/library/security/MS15-030 - 영문 : https://technet.microsoft.com/en-us/library/security/MS15-030 ##### □ 해결책 해당 시스템에 대한 마이크로소프트사의 취약점 패치 적용 [MS15-031] Schannel의 취약점으로 인한 보안 기능 우회 문제 ##### □ 영향 공격자가 영향 받는 시스템의 보안 기능 우회 ##### □ 설명 공격자가 TLS 연결에서 RSA 키의 길이를 강제로 다운그레이드 할 경우, 보안 기능 우회를 허용 ※ 최근, 이슈가 되고 있는 FREAK 취약점 보안 패치 관련취약점 : - Schannel 보안 기능 우회 취약점 ? (CVE-2015-1637) 영향 :보안 기능 우회 중요도 : 중요 ##### □ 해당시스템 참조사이트 참고 - 한글 : https://technet.microsoft.com/ko-kr/library/security/MS15-031 - 영문 : https://technet.microsoft.com/en-us/library/security/MS15-031 ##### □ 해결책 해당 시스템에 대한 마이크로소프트사의 취약점 패치 적용

Official advisory ↗

KISA KrCERT/CC · Korean · KNVD-4503‘FREAK’ SSL 취약점 주의 권고

#### ‘FREAK’ SSL 취약점 주의 권고 2015.03.04 개요 프랑스 국립 연구소(INRIA) 및 MS社에서는 SSL을 통해 강제로 취약한 RSA로 다운 그레이드 시킬 수 있는 취약점을 발견 ※ CVE-2015-0204 : OpenSSL s3_clnt.c의 ssl3_get_key exchange 함수에서 발생하는 취약점으로 공격자가 MITM(Man In The Middle Attack)을 통해 512비트 RSA로 다운 그레이드 시켜 정보를 유출시킬 수 있는 취약점[1] ※ MS社에서는 2015. 3. 5 (미국 시간 기준) Windows 시스템이 해당 취약점의 영향 받음을 추가로 확인(CVE-2015-1637)[2] 해당 시스템 영향을 받는 시스템 Openssl 0.9.8 대 0.9.8zd 이전 버전 Openssl 1.0.0 대 1.0.0p 이전 버전 Openssl 1.0.1 대 1.0.1k 이전 버전 이 밖에 취약한 OpenSSL을 사용한 Apple, Google, MS社 등의 제품 취약점 확인절차 (시스템 운영자) 시스템 측면 취약점 확인 아래의 명령어를 입력하여 취약점 유무 확인 openssl s_client ?connect [web site명 입력]:433 - cipher EXPORT [CVE-2015-0204에 취약하지 않은 화면] [CVE-2015-0204에 취약한 화면] 해결방안 (시스템 운영자) 해당 취약점에 영향 받는 버전 사용자 OpenSSL 1.0.2 버전으로 업그레이드( http://www.openssl.org/source/ ) 버전 업그레이드가 어려운 경우, OpenSSL 'RSA_EXPORT Cipher Suites'를 지원하거나 클라이언트로 'RSA_EXPORT suite'를 전송할 수 있는 모든 기능을 비활성화 시킬 것을 권장 ※ https://mozilla.github.io/server-side-tls/ssl-config-generator/ 사이트를 참고하여 권장사항으로 설정 [3] (윈도우 시스템 사용자) 해당 취약점

Official advisory ↗

Patch and workaround

Operational remediation based on structured source evidence.

Status ? Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.: Patch available
Affected: n/a
Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Action: Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround: No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.

Evidence and provenance

Published 6 Mar 2015 · Last source change 6 Aug 2024, 04:47 UTC · CWE-310

CVE recordCVE.org · 5.1

CVSS sourceNIST NVD

EPSS source

The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.

FIRST · tracked since 2026-09-01

European sourceENISA EUVD · EUVD-2015-1767

Product sourceUnavailable

Remediation sourceCVE/CNA references

CWE sourceNIST NVD

NVD statusNVD modified after enrichment

Missing structured fields: affected product. Missing data is not evidence of low risk; review the primary advisory.

Material change intelligence

What changed after publication

View recent updates ↗

1 Sep 2026, 02:42 UTC
ENISA EUVD mappingEUVD-2015-1767 was added to the official ENISA EUVD mapping for this CVE.
Before
not recorded
After
{"euvdId":"EUVD-2015-1767"}
ENISA EUVD ↗
6 Aug 2024, 04:47 UTC
Vendor guidanceAuthoritative vendor guidance changed: added patch: technet.microsoft.com/3046015; added remediation: technet.microsoft.com/3046015; removed remediation: docs.microsoft.com/ms15-031; 1 further additions.
Before
patch: docs.microsoft.com/ms15-031 · remediation: docs.microsoft.com/ms15-031
After
patch: docs.microsoft.com/ms15-031 · patch: technet.microsoft.com/3046015 · remediation: technet.microsoft.com/3046015 · 1 more references
technet.microsoft.com ↗
6 Aug 2024, 04:47 UTC
SeveritySeverity changed from Unknown to Medium.
Before
Unknown
After
Medium
NIST NVD ↗
6 Aug 2024, 04:47 UTC
CVSS scoreCVSS score changed from not recorded to 4.3 (CVSS 2.0 · NIST NVD · AV:N/AC:M/Au:N/C:N/I:P/A:N).
Before
not recorded
After
4.3 (CVSS 2.0 · NIST NVD · AV:N/AC:M/Au:N/C:N/I:P/A:N)
NIST NVD ↗
6 Aug 2024, 04:47 UTC
Catalogue recordCVE added to the BlackTree catalogue.
CNA ↗

2015-03-06CVE published

2024-08-06Fixed release or patch reference recorded

ENISA EUVD · EUVD-2015-1767↗CVE authority or vendor reference↗Vendor advisory↗Patch or update reference↗Official CVE record (CNA and ADP data)↗NVD record↗

Technical terms and abbreviations used in this report

CVE: Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS: Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS: Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE: Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA: CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP: Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD: National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT: A computer security incident response team that publishes warnings or coordinates incident response.
PoC: Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF: Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL: Living off the land: abuse of legitimate tools or system functions during an attack.

Affected product: security vulnerability

Published severity in operational context

Evidence used

Compensating controls

Verification

National CERT insights
?
CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

ENISA European Vulnerability Database

EUVD-2015-1767

What, why and how

Exploit reality and attack path

Official authority intelligence

Patch and workaround

Evidence and provenance

What changed after publication