Debian: Security Advisory (DLA-3187-1)

# SPDX-FileCopyrightText: 2022 Greenbone AG
# Some text descriptions might be excerpted from (a) referenced
# source(s), and are Copyright (C) by the respective right holder(s).
#
# SPDX-License-Identifier: GPL-2.0-only

if(description)
{
  script_oid("1.3.6.1.4.1.25623.1.0.893187");
  script_cve_id("CVE-2021-36369");
  script_tag(name:"creation_date", value:"2022-11-15 02:00:18 +0000 (Tue, 15 Nov 2022)");
  script_version("2024-02-02T05:06:08+0000");
  script_tag(name:"last_modification", value:"2024-02-02 05:06:08 +0000 (Fri, 02 Feb 2024)");
  script_tag(name:"cvss_base", value:"7.8");
  script_tag(name:"cvss_base_vector", value:"AV:N/AC:L/Au:N/C:N/I:C/A:N");
  script_tag(name:"severity_vector", value:"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N");
  script_tag(name:"severity_origin", value:"NVD");
  script_tag(name:"severity_date", value:"2022-10-14 20:03:13 +0000 (Fri, 14 Oct 2022)");

  script_name("Debian: Security Advisory (DLA-3187-1)");
  script_category(ACT_GATHER_INFO);
  script_copyright("Copyright (C) 2022 Greenbone AG");
  script_family("Debian Local Security Checks");
  script_dependencies("gather-package-list.nasl");
  script_mandatory_keys("ssh/login/debian_linux", "ssh/login/packages", re:"ssh/login/release=DEB10");

  script_xref(name:"Advisory-ID", value:"DLA-3187-1");
  script_xref(name:"URL", value:"https://www.debian.org/lts/security/2022/DLA-3187-1");
  script_xref(name:"URL", value:"https://security-tracker.debian.org/tracker/dropbear");
  script_xref(name:"URL", value:"https://wiki.debian.org/LTS");

  script_tag(name:"summary", value:"The remote host is missing an update for the Debian 'dropbear' package(s) announced via the DLA-3187-1 advisory.");

  script_tag(name:"vuldetect", value:"Checks if a vulnerable package version is present on the target host.");

  script_tag(name:"insight", value:"An issue was discovered in Dropbear, a relatively small SSH server and client. Due to a non-RFC-compliant check of the available authentication methods in the client-side SSH code, it was possible for an SSH server to change the login process in its favor. This attack can bypass additional security measures such as FIDO2 tokens or SSH-Askpass. Thus, it allows an attacker to abuse a forwarded agent for logging on to another server unnoticed.

For Debian 10 buster, this problem has been fixed in version 2018.76-5+deb10u2.

We recommend that you upgrade your dropbear packages.

For the detailed security status of dropbear please refer to its security tracker page at: [link moved to references]

Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: [link moved to references]");

  script_tag(name:"affected", value:"'dropbear' package(s) on Debian 10.");

  script_tag(name:"solution", value:"Please install the updated package(s).");

  script_tag(name:"solution_type", value:"VendorFix");
  script_tag(name:"qod_type", value:"package");

  exit(0);
}

include("revisions-lib.inc");
include("pkg-lib-deb.inc");

release = dpkg_get_ssh_release();
if(!release)
  exit(0);

res = "";
report = "";

if(release == "DEB10") {

  if(!isnull(res = isdpkgvuln(pkg:"dropbear", ver:"2018.76-5+deb10u2", rls:"DEB10"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"dropbear-bin", ver:"2018.76-5+deb10u2", rls:"DEB10"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"dropbear-initramfs", ver:"2018.76-5+deb10u2", rls:"DEB10"))) {
    report += res;
  }

  if(!isnull(res = isdpkgvuln(pkg:"dropbear-run", ver:"2018.76-5+deb10u2", rls:"DEB10"))) {
    report += res;
  }

  if(report != "") {
    security_message(data:report);
  } else if(__pkg_match) {
    exit(99);
  }
  exit(0);
}

exit(0);