Vulnerability Name:

CVE-2019-8460 (CCN-165880)

Assigned:2019-07-10
Published:2019-07-10
Updated:2021-08-02
Summary:OpenBSD kernel version <= 6.5 can be forced to create long chains of TCP SACK holes that causes very expensive calls to tcp_sack_option() for every incoming SACK packet which can lead to a denial of service.
CVSS v3 Severity:7.5 High (CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
6.5 Medium (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): High
7.5 High (CCN CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
6.5 Medium (CCN Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): High
CVSS v2 Severity:5.0 Medium (CVSS v2 Vector: AV:N/AC:L/Au:N/C:N/I:N/A:P)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Low
Authentication (Au): None
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): Partial
7.8 High (CCN CVSS v2 Vector: AV:N/AC:L/Au:N/C:N/I:N/A:C)
Exploitability Metrics:Access Vector (AV): Network
Access Complexity (AC): Low
Athentication (Au): None
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): Complete
Vulnerability Type:CWE-Other
Vulnerability Consequences:Denial of Service
References:Source: MITRE
Type: CNA
CVE-2019-8460

Source: XF
Type: UNKNOWN
openbsd-cve20198460-dos(165880)

Source: MISC
Type: Exploit, Vendor Advisory
https://ftp.openbsd.org/pub/OpenBSD/patches/6.5/common/006_tcpsack.patch.sig

Source: CCN
Type: OpenBSD GIT Repository
Received SACK options are managed by a linked list at the TCP socket

Source: MISC
Type: Patch, Third Party Advisory
https://github.com/openbsd/src/commit/ed8fdce754a5d8d14c09e989d8877707bd43906f

Source: MISC
Type: Exploit, Patch, Press/Media Coverage, Third Party Advisory
https://research.checkpoint.com/tcp-sack-security-issue-in-openbsd-cve-2019-8460/

Source: CONFIRM
Type: Third Party Advisory
https://security.netapp.com/advisory/ntap-20190905-0001/

Source: CCN
Type: WhiteSource Vulnerability Database
CVE-2019-8460

Vulnerable Configuration:Configuration 1:
  • cpe:/o:openbsd:openbsd:*:*:*:*:*:*:*:* (Version <= 6.5)

    • Configuration CCN 1:
  • cpe:/o:openbsd:openbsd:-:*:*:*:*:*:*:*
  • OR cpe:/o:openbsd:openbsd:6.5:*:*:*:*:*:*:*

    • * Denotes that component is vulnerable
    BACK
    openbsd openbsd *
    openbsd openbsd -
    openbsd openbsd 6.5