6.8 Medium
CVSS2
Attack Vector
NETWORK
Attack Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
AV:N/AC:M/Au:N/C:P/I:P/A:P
0.035 Low
EPSS
Percentile
91.6%
DenyHosts is designed to monitor SSH servers for repeated failed login attempts.
Daniel B. Cid discovered that DenyHosts used an incomplete regular expression to parse failed login attempts, a different issue than GLSA 200701-01.
A remote unauthenticated attacker can add arbitrary hosts into the blacklist, including the “all” keyword, by submitting specially crafted version identification strings to the SSH server banner. An attacker may use this to prevent legitimate users from accessing a host remotely.
There is no known workaround at this time.
All DenyHosts users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=app-admin/denyhosts-2.6-r1"
OS | Version | Architecture | Package | Version | Filename |
---|---|---|---|---|---|
Gentoo | any | all | app-admin/denyhosts | < 2.6-r1 | UNKNOWN |