Ubuntu.comUB:CVE-2015-4000CVE-2015-4000
4.3 Medium
CVSS2
Attack Vector
NETWORK
Attack Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:N/AC:M/Au:N/C:N/I:P/A:N
3.7 Low
CVSS3
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
LOW
Availability Impact
NONE
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
0.974 High
EPSS
Percentile
99.9%
The TLS protocol 1.2 and earlier, when a DHE_EXPORT ciphersuite is enabled
on a server but not on a client, does not properly convey a DHE_EXPORT
choice, which allows man-in-the-middle attackers to conduct
cipher-downgrade attacks by rewriting a ClientHello with DHE replaced by
DHE_EXPORT and then rewriting a ServerHello with DHE_EXPORT replaced by
DHE, aka the “Logjam” issue.
Notes
| Author | Note |
|---|---|
| mdeslaur | USN-2624-1 disables export ciphers completely in openssl USN-2625-1 disables export ciphers in apache2 in precise |
| seth-arnold | USN-2639-1 disables <768 bit dh parameters in openssl |
| mdeslaur | USN-2672-1 disables <768 bit dh parameters in nss |
| sbeattie | USN-2696-1 disables <768 bit dh parameters in openjdk-7 |
| mdeslaur | gnutls isn’t vulnerable to this issue and rejects small dh keys by default. On precise and trusty, the gnutls-cli tool unfortunately sets the minimum dh size to 512 using gnutls_dh_set_prime_bits(), so that must be disabled to test using the command line tool. |
| OS | Version | Architecture | Package | Version | Filename |
|---|---|---|---|---|---|
| ubuntu | 12.04 | noarch | apache2 | < 2.2.22-1ubuntu1.9 | UNKNOWN |
| ubuntu | 17.10 | noarch | firefox | < 39.0+build5-0ubuntu1 | UNKNOWN |
| ubuntu | 18.04 | noarch | firefox | < 39.0+build5-0ubuntu1 | UNKNOWN |
| ubuntu | 18.10 | noarch | firefox | < 39.0+build5-0ubuntu1 | UNKNOWN |
| ubuntu | 19.04 | noarch | firefox | < 39.0+build5-0ubuntu1 | UNKNOWN |
| ubuntu | 12.04 | noarch | firefox | < 39.0+build5-0ubuntu0.12.04.2 | UNKNOWN |
| ubuntu | 14.04 | noarch | firefox | < 39.0+build5-0ubuntu0.14.04.1 | UNKNOWN |
| ubuntu | 14.10 | noarch | firefox | < 39.0+build5-0ubuntu0.14.10.1 | UNKNOWN |
| ubuntu | 15.04 | noarch | firefox | < 39.0+build5-0ubuntu0.15.04.1 | UNKNOWN |
| ubuntu | 15.10 | noarch | firefox | < 39.0+build5-0ubuntu1 | UNKNOWN |
References
lists.gnutls.org/pipermail/gnutls-devel/2015-May/007597.html
access.redhat.com/articles/1456263
launchpad.net/bugs/cve/CVE-2015-4000
nohats.ca/wordpress/blog/2015/05/20/weakdh-and-ike-ipsec/
nvd.nist.gov/vuln/detail/CVE-2015-4000
security-tracker.debian.org/tracker/CVE-2015-4000
ubuntu.com/security/notices/USN-2624-1
ubuntu.com/security/notices/USN-2625-1
ubuntu.com/security/notices/USN-2639-1
ubuntu.com/security/notices/USN-2656-1
ubuntu.com/security/notices/USN-2656-2
ubuntu.com/security/notices/USN-2673-1
ubuntu.com/security/notices/USN-2696-1
ubuntu.com/security/notices/USN-2706-1
weakdh.org/
weakdh.org/imperfect-forward-secrecy.pdf
wiki.ubuntu.com/SecurityTeam/KnowledgeBase/LogJam
www.cve.org/CVERecord?id=CVE-2015-4000
www.openssl.org/blog/blog/2015/05/20/logjam-freak-upcoming-changes/
Related
4.3 Medium
CVSS2
Attack Vector
NETWORK
Attack Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:N/AC:M/Au:N/C:N/I:P/A:N
3.7 Low
CVSS3
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
LOW
Availability Impact
NONE
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
0.974 High
EPSS
Percentile
99.9%