cbcvebase.
CVE-2019-20500
published 2020-03-05

CVE-2019-20500: D-Link DWL-2600AP 4.2.0.15 Rev A devices have an authenticated OS command injection vulnerability via the Save Configuration functionality in the Web…

PriorityP184high7.8CVSS 3.1
AVLACLPRLUINSUCHIHAH
KEVITWEXPLOIT
CISA Known Exploited Vulnerabilitydue 2023-07-20
Exploited in the wild
EPSS
97.11%
99.9th percentile
D-Link DWL-2600AP 4.2.0.15 Rev A devices have an authenticated OS command injection vulnerability via the Save Configuration functionality in the Web interface, using shell metacharacters in the admin.cgi?action=config_save configBackup or downloadServerip parameter.

Affected

1 ranges
VendorProductVersion rangeFixed in
dlinkdwl-2600ap_firmware<= 4.2.0.15

Detection & IOCsextracted from sources · hover to see the quote

url/admin.cgi?action=config_save
url/admin.cgi?action=config_restore
url/admin.cgi?action=upgrade
path/var/passwd
commandcheck_tftp=up&configBackup=;whoami;whoami;.xml&downloadServerip=;cat /var/passwd;cat /var/passwd
snort
alert http any any -> $HOME_NET any (msg:"ET WEB_SPECIFIC_APPS D-Link DWL-2600AP Command Injection Attempt (CVE-2019-20499, CVE-2019-20500, CVE-2019-20501)"; flow:established,to_server; http.method; content:"POST"; http.uri; content:"/admin.cgi|3f|action|3d|"; startswith; fast_pattern; pcre:"/^(?:upgrade|config_(?:save|restore))$/R"; http.request_body; pcre:"/(?:firmware(?:Serverip|Restore)|config(?:Backup|Restore|Serverip)|downloadServerip)[^\x26]*?(?:(?:\x3b|%3[Bb])|(?:\x0a|%0[Aa])|(?:\x60|%60)|(?:\x7c|%7[Cc])|(?:\x24|%24))+/P"; reference:cve,2019-20499; reference:cve,2019-20500; reference:cve,2019-20501; reference:url,unit42.paloaltonetworks.com/mirai-variant-targets-iot-exploits/; reference:url,www.exploit-db.com/exploits/46841; classtype:attempted-admin; sid:2057317; rev:1; metadata:attack_target Networking_Equipment, tls_state plaintext, created_at 2024_11_07, cve CVE_2019_20499, deployment Perimeter, deployment Internal, performance_impact Low, confidence High, signature_severity Major, tag Exploit, updated_at 2024_11_07; target:dest_ip;)
  • Look for POST requests to /admin.cgi with action=config_save, action=config_restore, or action=upgrade containing shell metacharacters (;, |, `, $, newline) in the configBackup, downloadServerip, configRestore, configServerip, firmwareRestore, or firmwareServerip parameters.
  • The Emergint Threats Snort rule (sid:2057317) matches POST to /admin.cgi|3f|action|3d| with URI matching upgrade|config_save|config_restore and body containing shell metacharacters (%3B, %0A, %60, %7C, %24) in the vulnerable parameters.
  • Exploitation requires authenticated access; monitor for successful logins to the D-Link DWL-2600AP web interface followed immediately by POST requests to the above endpoints.
  • The exploit payload pattern uses semicolon-delimited commands repeated twice (e.g., ;command1;same_command1;command2;command2) — look for this doubling pattern in POST body parameters.
  • This vulnerability has been observed exploited by Mirai variants; correlate detections with known Mirai botnet infrastructure.
  • ·The vulnerability is only exploitable by authenticated users; unauthenticated exploitation is not possible without valid credentials.
  • ·Affected firmware is specifically version 4.2.0.15 on Hardware Version A1; other versions may not be vulnerable.
  • ·The ET Snort rule (sid:2057317) covers three related CVEs (CVE-2019-20499, CVE-2019-20500, CVE-2019-20501) across all three vulnerable actions; a single alert may correspond to any of the three injection points.

CVSS provenance

nvdv3.17.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
nvdv2.07.2HIGHAV:L/AC:L/Au:N/C:C/I:C/A:C
vulncheck7.8HIGH
cisa7.8HIGH
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