cbcvebase.
CVE-2019-20215
published 2020-01-29

CVE-2019-20215: D-Link DIR-859 1.05 and 1.06B01 Beta01 devices allow remote attackers to execute arbitrary OS commands via a urn: to the M-SEARCH method in ssdpcgi() in…

PriorityP183critical9.8CVSS 3.1
AVNACLPRNUINSUCHIHAH
EXPLOIT
EPSS
75.11%
99.5th percentile
D-Link DIR-859 1.05 and 1.06B01 Beta01 devices allow remote attackers to execute arbitrary OS commands via a urn: to the M-SEARCH method in ssdpcgi() in /htdocs/cgibin, because HTTP_ST is mishandled. The value of the urn: service/device is checked with the strstr function, which allows an attacker to concatenate arbitrary commands separated by shell metacharacters.

Affected

2 ranges
VendorProductVersion rangeFixed in
dlinkdir-859_firmware
dlinkdir-859_firmware

Detection & IOCsextracted from sources · hover to see the quote

port1900
path/htdocs/cgibin
commandM-SEARCH * HTTP/1.1 Host:239.255.255.250: 1900 ST:urn:device:1;`<cmd>` Man:"ssdp:discover" MX:2
commandurn:device:1;`<cmd>`
commanduuid:`<cmd>`
  • Detect exploitation attempts by monitoring UDP traffic on port 1900 for M-SEARCH packets containing shell metacharacters (backticks, semicolons) in the ST (Search Target) header field, particularly patterns matching 'urn:*;`' or 'uuid:`'.
  • The exploit uses two injection vectors via the ST header: URN-based ('urn:device:1;`cmd`') and UUID-based ('uuid:`cmd`'). Both should be covered in detection signatures.
  • The vulnerability is in ssdpcgi() where HTTP_ST is mishandled via strstr(); monitor for process spawning from ssdpcgi or /htdocs/cgibin on D-Link devices, especially child shell processes.
  • The Metasploit module defaults to MIPSBE architecture with a meterpreter_reverse_tcp payload and uses wget or echo as the cmdstager flavor; monitor for outbound wget connections or unusual echo-based file writes following UPnP traffic on affected devices.
  • ·The exploit targets UDP port 1900 (UPnP/SSDP); network-level blocking or rate-limiting of inbound UDP/1900 from untrusted sources will mitigate exploitation. UPnP is enabled by default on most affected D-Link devices.
  • ·Staged meterpreter payloads may cause crashes on target; attackers are likely to use stageless payloads, which may affect payload size and delivery method signatures.
  • ·Some D-Link devices lack the wget command; attackers may fall back to echo-based cmdstager, altering the post-exploitation payload delivery pattern.

CVSS provenance

nvdv3.19.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
nvdv2.010.0CRITICALAV:N/AC:L/Au:N/C:C/I:C/A:C
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