cbcvebase.
CVE-2017-14494
published 2017-10-03

CVE-2017-14494: dnsmasq before 2.78, when configured as a relay, allows remote attackers to obtain sensitive memory information via vectors involving handling DHCPv6 forwarded…

PriorityP260medium5.9CVSS 3.0
AVNACHPRNUINSUCHINAN
EXPLOIT
EPSS
67.55%
99.2th percentile
dnsmasq before 2.78, when configured as a relay, allows remote attackers to obtain sensitive memory information via vectors involving handling DHCPv6 forwarded requests.

Affected

19 ranges
VendorProductVersion rangeFixed in
canonicalubuntu_linux
canonicalubuntu_linux
canonicalubuntu_linux
debiandebian_linux
debiandebian_linux
debiandebian_linux
debiandnsmasq< dnsmasq 2.78-1 (bookworm)dnsmasq 2.78-1 (bookworm)
novellleap
novellleap
redhatenterprise_linux_desktop
redhatenterprise_linux_server
redhatenterprise_linux_workstation
thekelleysdnsmasq<= 2.77
thekelleysdnsmasq>= 0 < 2.78-12.78-1
thekelleysdnsmasq>= 0 < 2.78-12.78-1
thekelleysdnsmasq>= 0 < 2.78-12.78-1
thekelleysdnsmasq>= 0 < 2.78-12.78-1
thekelleysdnsmasq>= 0 < 2.68-1ubuntu0.22.68-1ubuntu0.2
thekelleysdnsmasq>= 0 < 2.75-1ubuntu0.16.04.32.75-1ubuntu0.16.04.3

Detection & IOCsextracted from sources · hover to see the quote

port547
port547
commandDHCP6RELAYFORW (type byte 0x0c / u8(12))
commandOption 9 - OPTION6_RELAY_MSG with oversized length field
urlhttp://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commitdiff;h=33e3f1029c9ec6c63e430ff51063a6301d4b2262
urlhttps://github.com/google/security-research-pocs/tree/master/vulnerabilities/dnsmasq
  • Detect crafted DHCPv6 RELAY-FORW packets (message type 12) sent to UDP port 547 where the OPTION6_RELAY_MSG (option 9) length field exceeds the actual packet buffer size — this is the memory-leak trigger condition.
  • Monitor for DHCPv6 relay responses (from dnsmasq acting as relay) that are significantly larger than the originating request — the PoC leaks up to 32 KB of process memory starting at buffer+38.
  • Flag inbound DHCPv6 packets on UDP/547 containing message type 0x0c (RELAY-FORW) with option type 9 (RELAY_MSG) whose declared length field is larger than the remaining packet bytes.
  • Exploitation requires the attacker to be on the local network segment; prioritise monitoring on internal DHCPv6 relay-enabled interfaces rather than internet-facing ones.
  • ·This vulnerability only affects dnsmasq when configured as a DHCPv6 relay; instances not acting as a relay are not exploitable.
  • ·dnsmasq on RHEL 5 and RHEL 6 does not include the DHCPv6 relay code and is therefore not affected; detection rules targeting those platforms are unnecessary.
  • ·The exploit requires knowledge of the target's DUID (DHCPv6 Unique Identifier); absence of an automated DUID-discovery method slightly raises the bar for opportunistic attackers.

CVSS provenance

nvdv3.05.9MEDIUMCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
nvdv2.04.3MEDIUMAV:N/AC:M/Au:N/C:P/I:N/A:N
osv9.8CRITICAL
vendor_ubuntu9.8CRITICAL
vendor_debian5.9MEDIUM
vendor_redhat5.9MEDIUM
CVEs like this are exactly what “Exploited This Week” covers.

Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.