Analyst readout for executives and security teams
Plain-English summary
CVE-2013-2566 is a weakness in using the old RC4 cipher with TLS/SSL. RC4 leaks tiny statistical clues across many encrypted sessions. An attacker who can collect enough similar traffic may recover sensitive plaintext, such as repeated secrets. This is mainly a legacy-configuration risk.
Executive priority
Prioritize remediation as cryptographic hygiene and compliance work. Treat as higher urgency for services carrying authentication cookies, session identifiers, or regulated data. Do not assume active exploitation from the provided sources, but avoid accepting RC4 exposure in production.
Technical view
RC4 in TLS/SSL has single-byte biases that can support plaintext-recovery through statistical analysis of large volumes of ciphertext sharing the same plaintext. The CVSS 3.1 score is 5.9 with high attack complexity and confidentiality impact only. The issue maps to CWE-327, use of a broken or risky cryptographic algorithm.
Likely exposure
Exposure exists where servers, clients, appliances, or applications still allow RC4 cipher suites for TLS/SSL. The source data does not identify a single affected product list; it references multiple vendor advisories, indicating broad legacy ecosystem impact.
Exploitation context
The CVE is not listed as KEV in the provided data. Sources describe a statistical cryptographic attack requiring many sessions with repeated plaintext, not simple one-shot exploitation. Risk rises for high-traffic services that still negotiate RC4 and carry repeated secrets.
Researcher notes
This is a protocol/algorithm weakness rather than a conventional memory-safety bug. Validate negotiation behavior, not just package versions. Vendor advisories may have product-specific updates, but the core remediation is eliminating RC4 from TLS/SSL use.
Mitigation direction
- Disable RC4 cipher suites for all TLS/SSL services and clients.
- Prefer modern TLS versions and strong authenticated cipher suites.
- Apply relevant vendor updates from affected platform advisories.
- Check current vendor hardening guidance for legacy products.
- Retire systems that cannot operate without RC4.
Validation and detection
- Inventory internet-facing and internal TLS endpoints.
- Verify no endpoint negotiates RC4 cipher suites.
- Review load balancer, proxy, server, and appliance TLS policies.
- Confirm vulnerability scanners no longer report RC4 support.
- Check exception lists for legacy client compatibility dependencies.
Public sources used
Based on public source material and reviewed before publication.
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
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-327: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2013-2566 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 5.9 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
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.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N2.23.6CISA-ADPVulnerability scoring details
Base CVSS 3.1 score
5.9MediumVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- http://www.oracle.com/technetwork/security-advisory/cpujan2018-3236628.htmlCVE reference, mitre · x_refsource_CONFIRM
- http://blog.cryptographyengineering.com/2013/03/attack-of-week-rc4-is-kind-of-broken-in.htmlCVE reference, mitre · x_refsource_MISC
- 58796CVE reference, mitre · vdb-entry, x_refsource_BID
- http://www.oracle.com/technetwork/security-advisory/cpujul2016-2881720.htmlCVE reference, mitre · x_refsource_CONFIRM
- http://cr.yp.to/talks/2013.03.12/slides.pdfCVE reference, mitre · x_refsource_MISC
- HPSBGN03324CVE reference, mitre · vendor-advisory, x_refsource_HP
- http://www.oracle.com/technetwork/security-advisory/cpuoct2016-2881722.htmlCVE reference, mitre · x_refsource_CONFIRM
- GLSA-201504-01CVE reference, mitre · vendor-advisory, x_refsource_GENTOO
- GLSA-201406-19CVE reference, mitre · vendor-advisory, x_refsource_GENTOO
- http://www.oracle.com/technetwork/security-advisory/cpuoct2017-3236626.htmlCVE reference, mitre · x_refsource_CONFIRM
- USN-2031-1CVE reference, mitre · vendor-advisory, x_refsource_UBUNTU
- USN-2032-1CVE reference, mitre · vendor-advisory, x_refsource_UBUNTU
- http://my.opera.com/securitygroup/blog/2013/03/20/on-the-precariousness-of-rc4CVE reference, mitre · x_refsource_CONFIRM
- http://www.oracle.com/technetwork/security-advisory/cpuapr2016v3-2985753.htmlCVE reference, mitre · x_refsource_CONFIRM
- http://www.opera.com/security/advisory/1046CVE reference, mitre · x_refsource_CONFIRM
- http://kb.juniper.net/InfoCenter/index?page=content&id=JSA10705CVE reference, mitre · x_refsource_CONFIRM
- https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05336888CVE reference, mitre · x_refsource_CONFIRM
- http://www.mozilla.org/security/announce/2013/mfsa2013-103.htmlCVE reference, mitre · x_refsource_CONFIRM
- http://www.isg.rhul.ac.uk/tls/CVE reference, mitre · x_refsource_MISC
- http://www.opera.com/docs/changelogs/unified/1215/CVE reference, mitre · x_refsource_CONFIRM
- https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05289935CVE reference, mitre · x_refsource_CONFIRM
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Use of a Broken or Risky Cryptographic Algorithm
Use of a Broken or Risky Cryptographic Algorithm represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.