CVE-2018-19524: An issue was discovered on Shenzhen Skyworth DT741 Converged Intelligent Terminal (G/EPON+IPTV) SDOTBGN1, DT721-cb SDOTBGN1, and DT741-cb SDOTBGN1 devices. A…

PriorityP271critical9.8CVSS 3.0

AVNACLPRNUINSUCHIHAH

EXPLOIT

EPSS

50.52%

98.8th percentile

An issue was discovered on Shenzhen Skyworth DT741 Converged Intelligent Terminal (G/EPON+IPTV) SDOTBGN1, DT721-cb SDOTBGN1, and DT741-cb SDOTBGN1 devices. A long password to the Web_passwd function allows remote attackers to cause a denial of service (segmentation fault) or achieve unauthenticated remote code execution because of control of registers S0 through S4 and T4 through T7.

Affected

3 ranges

Vendor	Product	Version range	Fixed in
skyworthdigital	dt721-cb_firmware	—	—
skyworthdigital	dt740_firmware	—	—
skyworthdigital	dt741-cb_firmware	—	—

Detection & IOCsextracted from sources · hover to see the quote

url/cgi-bin/index2.asp↗

cookieLoginTimes=0↗

commandUsername=Bufferoverflow&Logoff=0&LoginTimes=1&LoginTimes_Zero=0&value_one=1&Password1=xss&Password2=xss&logintype=usr&Password=AAA...(x999)↗

bytes↗

\xA0\x0E\xA2\x18

→Alert on HTTP POST requests to /cgi-bin/index2.asp with Content-Length >= 1714 and a Password parameter value exceeding normal bounds, as this matches the PoC exploit structure. ↗
→The exploit targets the web_passwd function inside the boa web server implementation; monitor for segmentation faults or crashes in the boa process on affected Skyworth GPON devices. ↗
→The return address bytes \xA0\x0E\xA2\x18 appear in the exploit payload; scan for this byte sequence in HTTP POST bodies to /cgi-bin/index2.asp. ↗
→Unauthenticated exploitation: the attack requires no prior authentication. Flag any unauthenticated POST to /cgi-bin/index2.asp with an anomalously large Password field from external/untrusted sources. ↗

·The register control addresses (T4, T7, T6, S0–S3) used in the PoC are placeholder labels, not real addresses — actual exploitation requires device/libc-specific offsets that vary per firmware build. ↗
·No official vendor mitigation was available at time of disclosure; affected firmware versions are listed as 'Multiple versions' (SDOTBGN1), so version-based filtering alone is insufficient. ↗

CVSS provenance

nvdv3.09.8CRITICALCVSS:3.0/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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