Bouncy Castle BKS-V1 keystore files vulnerable to trivial hash collisions

Also known as GHSA-8477-3v39-ggpm

Published 8 y ago 2018-04-16 · modified 4 mo ago 2026-06-17 · JSON

CVSS

4.4

v3.1 · NVD

CISA KEV

not known exploited

EPSS

0.3%

percentile 18%

Public exploits

none known

The default BKS keystore use an HMAC that is only 16 bits long, which can allow an attacker to compromise the integrity of a BKS keystore. Bouncy Castle release 1.47 changes the BKS format to a format which uses a 160 bit HMAC instead. This applies to any BKS keystore generated prior to BC 1.47. For situations where people need to create the files for legacy reasons a specific keystore type "BKS-V1" was introduced in 1.49. It should be noted that the use of "BKS-V1" is discouraged by the library authors and should only be used where it is otherwise safe to do so, as in where the use of a 16 bit checksum for the file integrity check is not going to cause a security issue in itself.

Exploit prediction (EPSS)

0.26% probability of exploitation in the next 30 days, higher than 18% of all scored CVEs.

CVSS scores

Assigned by	Version	Score	Vector
NVD	3.1	4.4	`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N`
NVD	2.0	3.6	`AV:L/AC:L/Au:N/C:P/I:P/A:N`
GitHub	3.1	4.4	`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N`

Affected packages

Ecosystem	Package	Affected	Fixed in
maven	`org.bouncycastle:bcprov-jdk15on`	<1.50	1.50

Affected products

Legion of the Bouncy Castle Bouncy Castle

Classification

Weakness

CWE-327 Use of a Broken or Risky Cryptographic Algorithm
CWE-354 Improper Validation of Integrity Check Value

References

securityfocus.com /bid/103453 · vdb-entry, x_refsource_BID, x_transferred
access.redhat.com /errata/RHSA-2018:2927 · vendor-advisory, x_refsource_REDHAT, x_transferred
kb.cert.org /vuls/id/306792 · third-party-advisory, x_refsource_CERT-VN, x_transferred
bouncycastle.org /releasenotes.html · x_refsource_MISC, x_transferred
oracle.com /security-alerts/cpuoct2020.html · x_refsource_MISC, x_transferred
nvd.nist.gov /vuln/detail/CVE-2018-5382 · advisory

Sources

CVE List: CVE-2018-5382
GitHub Advisory: GHSA-8477-3v39-ggpm
NVD: CVE-2018-5382

vulnwire keeps one entry per vulnerability: the CVE id wins, then GHSA; records that alias each other are merged. Machine-readable: JSON.

Summary