CVE-2013-6890
published 2013-12-23CVE-2013-6890: denyhosts 2.6 uses an incorrect regular expression when analyzing authentication logs, which allows remote attackers to cause a denial of service (incorrect…
PriorityP432medium5CVSS 2.0
AVNACLAuNCNINAP
EXPLOIT
EPSS
8.90%
94.6th percentile
denyhosts 2.6 uses an incorrect regular expression when analyzing authentication logs, which allows remote attackers to cause a denial of service (incorrect block of IP addresses) via crafted login names.
Affected
4 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | debian_linux | — | — |
| debian | debian_linux | — | — |
| debian | debian_linux | — | — |
| phil_schwartz | denyhosts | — | — |
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Bugzilla
CVE-2013-6890 denyhosts: remote denial of ssh service [epel-all]
bugzilla·2013-12-23·CVSS 5.0
CVE-2013-6890 [MEDIUM] CVE-2013-6890 denyhosts: remote denial of ssh service [epel-all]
CVE-2013-6890 denyhosts: remote denial of ssh service [epel-all]
This is an automatically created tracking bug! It was created to ensure
that one or more security vulnerabilities are fixed in affected versions
of Fedora EPEL.
For comments that are specific to the vulnerability please use bugs filed
against the "Security Response" product referenced in the "Blocks" field.
For more information see:
http://fedoraproject.org/wiki/Security/TrackingBugs
When creating a Bodhi update request, please use the bodhi submission link
noted in the next comment(s). This will include the bug IDs of this
tracking bug as well as the relevant top-level CVE bugs.
Please also mention the CVE IDs being fixed in the RPM changelog and the
Bodhi notes field when available.
Please note: this issue affects mul
Bugzilla
CVE-2013-6890 denyhosts: remote denial of ssh service [fedora-all]
bugzilla·2013-12-23·CVSS 5.0
CVE-2013-6890 [MEDIUM] CVE-2013-6890 denyhosts: remote denial of ssh service [fedora-all]
CVE-2013-6890 denyhosts: remote denial of ssh service [fedora-all]
This is an automatically created tracking bug! It was created to ensure
that one or more security vulnerabilities are fixed in affected versions
of Fedora.
For comments that are specific to the vulnerability please use bugs filed
against the "Security Response" product referenced in the "Blocks" field.
For more information see:
http://fedoraproject.org/wiki/Security/TrackingBugs
When creating a Bodhi update request, please use the bodhi submission link
noted in the next comment(s). This will include the bug IDs of this
tracking bug as well as the relevant top-level CVE bugs.
Please also mention the CVE IDs being fixed in the RPM changelog and the
Bodhi notes field when available.
Please note: this issue affects multip
Bugzilla
CVE-2013-6890 denyhosts: remote denial of ssh service
bugzilla·2013-12-23·CVSS 5.0
CVE-2013-6890 [MEDIUM] CVE-2013-6890 denyhosts: remote denial of ssh service
CVE-2013-6890 denyhosts: remote denial of ssh service
It was found that denyhosts, a tool preventing SSH brute-force attacks, could be used to perform remote denial of service against the SSH daemon.
Incorrectly specified regular expressions used to detect brute force attacks in authentication logs could be exploited by a malicious user to forge crafted login names in order to make denyhosts ban arbitrary IP addresses.
A solution is proposed by the reporter, which is to tighten up the regular expressions for matching log file entries. Specifically including the $ pattern to match the end of log lines.
References:
http://seclists.org/oss-sec/2013/q4/535
http://www.debian.org/security/2013/dsa-2826
Discussion:
Created denyhosts tracking bugs for this issue:
Affects: fedora-all [bug 10
http://seclists.org/oss-sec/2013/q4/535http://secunia.com/advisories/56239http://www.debian.org/security/2013/dsa-2826https://bugzilla.redhat.com/show_bug.cgi?id=1045982http://seclists.org/oss-sec/2013/q4/535http://secunia.com/advisories/56239http://www.debian.org/security/2013/dsa-2826https://bugzilla.redhat.com/show_bug.cgi?id=1045982
2013-12-23
Published