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Debian LinuxOperating system · Debian

CVE-2018-0497

MEDIUM · 5.9 CVSS v3.0 Published 2018-07-28
Fix available
A fix is available. Upgrade to 2.1.14 / 2.7.5 or later.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
ARM mbed TLS before 2.12.0, before 2.7.5, and before 2.1.14 allows remote attackers to achieve partial plaintext recovery (for a CBC based ciphersuite) via a timing-based side-channel attack. This vulnerability exists because of an incorrect fix (with a wrong SHA-384 calculation) for CVE-2013-0169.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

ARM mbed TLS contains a timing-based side-channel vulnerability in CBC mode ciphersuite handling that allows partial plaintext recovery. The flaw stems from an incorrect fix for CVE-2013-0169 (Lucky Thirteen), where the SHA-384 calculation used in padding validation was implemented incorrectly, creating a detectable timing difference that can be exploited remotely.

MitigationUpgrade mbed TLS to version 2.12.0, 2.7.5, or 2.1.14 or later to obtain the corrected SHA-384 implementation. Alternatively, prefer AEAD ciphersuites (GCM, CCM) over CBC-based ciphersuites to eliminate this attack surface.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Debian LinuxOperating system
Affected:= 8.0= 9.0
Mbed TlsApplication
Affected:< 2.1.14>= 2.2.0, < 2.7.5>= 2.8.0, < 2.12.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify if mbed TLS libraries are installed
    Search for mbed TLS library files: run 'dpkg -l | grep mbed' on Debian systems, or check for files named 'libmbedtls.so', 'libmbedcrypto.so', or 'libmbedx509.so' in standard library directories (/usr/lib, /lib)
    Affected if Any mbed TLS library package is found on the system
  2. Determine the installed mbed TLS version
    Run 'dpkg -l | grep mbed' to list installed mbed TLS packages with their versions, or use 'openssl version -a' if linked against mbed TLS, or check library file metadata using 'dpkg -s <package-name>'
    Affected if The version displayed falls within any of these ranges: < 2.1.14, >= 2.2.0 and < 2.7.5, >= 2.8.0 and < 2.12.0
  3. Check if TLSCBC mode cipher suites are enabled or available
    Review TLS server configuration or application settings to determine if CBC-based cipher suites (such as TLS_RSA_WITH_AES_128_CBC_SHA, TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA, etc.) are listed in the enabled cipher suite set
    Affected if CBC-mode cipher suites are included in the enabled TLS cipher suite list and the server accepts CBC-based connections
  4. Verify the vulnerable SHA-384 padding check code is in use
    If possible, inspect TLS handshake traffic or server configuration to confirm that cipher suites using SHA-384 in HMAC (e.g., AES_256_CBC_SHA384) are negotiated, or check if the mbed TLS source linked against the application includes the vulnerable SHA-384 padding validation routine
    Affected if A TLS connection negotiates a CBC-mode cipher suite that uses SHA-384 for HMAC-based padding validation

The system is affected if a vulnerable mbed TLS version (as identified in step 2) is installed AND the system is configured to accept or use CBC-mode cipher suites in TLS connections.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to 2.1.14 / 2.7.5 / 2.12.0 or later
Fixed in 2.1.142.7.52.12.0
Interim mitigation

Upgrade mbed TLS to version 2.12.0, 2.7.5, or 2.1.14 or later to obtain the corrected SHA-384 implementation. Alternatively, prefer AEAD ciphersuites (GCM, CCM) over CBC-based ciphersuites to eliminate this attack surface.

Fix this in Debian Linux Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing12.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,760
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2018-0497 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data