A xrdp security update has been released for Debian GNU/Linux 9 to address an issue where xrdp-sesman service in xrdp can be crashed by connecting over port 3350 and supplying a malicious payload.

DLA 2319-1: xrdp security update

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Debian LTS Advisory DLA-2319-1 debian-lts@lists.debian.org
  https://www.debian.org/lts/security/ Abhijith PA
August 09, 2020   https://wiki.debian.org/LTS
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Package : xrdp
Version : 0.9.1-9+deb9u4
CVE ID : CVE-2020-4044
Debian Bug : 964573

xrdp-sesman service in xrdp can be crashed by connecting over port 3350
and supplying a malicious payload. Once the xrdp-sesman process is dead,
an unprivileged attacker on the server could then proceed to start their
own imposter sesman service listening on port 3350. This will allow them
to capture any user credentials that are submitted to XRDP and approve or
reject arbitrary login credentials. For xorgxrdp sessions in particular,
this allows an unauthorized user to hijack an existing session. This is a
buffer overflow attack, so there may be a risk of arbitrary code
execution as well.

For Debian 9 stretch, this problem has been fixed in version
0.9.1-9+deb9u4.

We recommend that you upgrade your xrdp packages.

For the detailed security status of xrdp please refer to
its security tracker page at:
  https://security-tracker.debian.org/tracker/xrdp

Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at:   https://wiki.debian.org/LTS