Amazon Linux 2023 : amazon-cloudwatch-agent (ALAS2023-2025-1358)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux 2023 Security Advisory ALAS2023-2025-1358.
##

include('compat.inc');

if (description)
{
  script_id(282383);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/02/24");

  script_cve_id(
    "CVE-2025-47914",
    "CVE-2025-58181",
    "CVE-2025-61727",
    "CVE-2025-61729",
    "CVE-2025-68156"
  );
  script_xref(name:"IAVB", value:"2025-B-0194-S");

  script_name(english:"Amazon Linux 2023 : amazon-cloudwatch-agent (ALAS2023-2025-1358)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Amazon Linux 2023 host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2025-1358 advisory.

    SSH Agent servers do not validate the size of messages when processing new identity requests, which may
    cause the program to panic if the message is malformed due to an out of bounds read. (CVE-2025-47914)

    SSH servers parsing GSSAPI authentication requests do not validate the number of mechanisms specified in
    the request, allowing an attacker to cause unbounded memory consumption. (CVE-2025-58181)

    crypto/x509: excluded subdomain constraint does not restrict wildcard SANs

    An excluded subdomain constraint in a certificate chain does not restrict the usage of wildcard SANs in
    the leaf certificate. For example a constraint that excludes the subdomain test.example.com does not
    prevent a leaf certificate from claiming the SAN *.example.com. (CVE-2025-61727)

    Within HostnameError.Error(), when constructing an error string, there is no limit to the number of hosts
    that will be printed out. Furthermore, the error string is constructed by repeated string concatenation,
    leading to quadratic runtime. Therefore, a certificate provided by a malicious actor can result in
    excessive resource consumption. (CVE-2025-61729)

    Expr is an expression language and expression evaluation for Go. Prior to version 1.17.7, several builtin
    functions in Expr, including `flatten`, `min`, `max`, `mean`, and `median`, perform recursive traversal
    over user-provided data structures without enforcing a maximum recursion depth. If the evaluation
    environment contains deeply nested or cyclic data structures, these functions may recurse indefinitely
    until exceed the Go runtime stack limit. This results in a stack overflow panic, causing the host
    application to crash. While exploitability depends on whether an attacker can influence or inject cyclic
    or pathologically deep data into theevaluation environment, this behavior represents a denial-of-service
    (DoS) risk and affects overall library robustness. Instead of returning a recoverable evaluation error,
    the process may terminate unexpectedly. In affected versions, evaluation of expressions that invoke
    certain builtin functions on untrusted or insufficiently validated data structures can lead to a process-
    level crash due to stack exhaustion. This issue is most relevant in scenarios where Expr is used to
    evaluate expressions against externally supplied or dynamically constructed environments; cyclic
    references (directly or indirectly) can be introduced into arrays, maps, or structs; and there are no
    application-level safeguards preventing deeply nested input data. In typical use cases with controlled,
    acyclic data, the issue may not manifest. However, when present, the resulting panic can be used to
    reliably crash the application, constituting a denial of service. The issue has been fixed in the v1.17.7
    versions of Expr. The patch introduces a maximum recursion depth limit for affected builtin functions.
    When this limit is exceeded, evaluation aborts gracefully and returns a descriptive error instead of
    panicking. Additionally, the maximum depth can be customized by users via `builtin.MaxDepth`, allowing
    applications with legitimate deep structures to raise the limit in a controlled manner. Users are strongly
    encouraged to upgrade to the patched release, which includes both the recursion guard and comprehensive
    test coverage to prevent regressions. For users who cannot immediately upgrade, some mitigations are
    recommended. Ensure that evaluation environments cannot contain cyclic references, validate or sanitize
    externally supplied data structures before passing them to Expr, and/or wrap expression evaluation with
    panic recovery to prevent a full process crash (as a last-resort defensive measure). These workarounds
    reduce risk but do not fully eliminate the issue without the patch. (CVE-2025-68156)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version
number.");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com//AL2023/ALAS2023-2025-1358.html");
  script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/faqs.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2025-47914.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2025-58181.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2025-61727.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2025-61729.html");
  script_set_attribute(attribute:"see_also", value:"https://explore.alas.aws.amazon.com/CVE-2025-68156.html");
  script_set_attribute(attribute:"solution", value:
"Run 'dnf update amazon-cloudwatch-agent --releasever 2023.10.20260105' or
  or 'dnf update --advisory ALAS2023-2025-1358 --releasever 2023.10.20260105' to update your system.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2025-61727");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");

  script_set_attribute(attribute:"vuln_publication_date", value:"2025/11/19");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/01/07");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/01/08");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:amazon-cloudwatch-agent");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux:2023");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Amazon Linux Local Security Checks");

  script_copyright(english:"This script is Copyright (C) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/AmazonLinux/release", "Host/AmazonLinux/rpm-list");

  exit(0);
}

include("rpm.inc");

if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);

var alas_release = get_kb_item("Host/AmazonLinux/release");
if (isnull(alas_release) || !strlen(alas_release)) audit(AUDIT_OS_NOT, "Amazon Linux");
var os_ver = pregmatch(pattern: "^AL(A|\d+|-\d+)", string:alas_release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, "Amazon Linux");
os_ver = os_ver[1];
if (os_ver != "-2023")
{
  if (os_ver == 'A') os_ver = 'AMI';
  audit(AUDIT_OS_NOT, "Amazon Linux 2023", "Amazon Linux " + os_ver);
}

if (!get_kb_item("Host/AmazonLinux/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);

var pkgs = [
    {'reference':'amazon-cloudwatch-agent-1.300062.1-1.amzn2023', 'cpu':'aarch64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE},
    {'reference':'amazon-cloudwatch-agent-1.300062.1-1.amzn2023', 'cpu':'x86_64', 'release':'AL-2023', 'rpm_spec_vers_cmp':TRUE}
];

var flag = 0;
foreach var package_array ( pkgs ) {
  var reference = NULL;
  var _release = NULL;
  var sp = NULL;
  var _cpu = NULL;
  var el_string = NULL;
  var rpm_spec_vers_cmp = NULL;
  var epoch = NULL;
  var allowmaj = NULL;
  var exists_check = NULL;
  var cves = NULL;
  if (!empty_or_null(package_array['reference'])) reference = package_array['reference'];
  if (!empty_or_null(package_array['release'])) _release = package_array['release'];
  if (!empty_or_null(package_array['sp'])) sp = package_array['sp'];
  if (!empty_or_null(package_array['cpu'])) _cpu = package_array['cpu'];
  if (!empty_or_null(package_array['el_string'])) el_string = package_array['el_string'];
  if (!empty_or_null(package_array['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = package_array['rpm_spec_vers_cmp'];
  if (!empty_or_null(package_array['epoch'])) epoch = package_array['epoch'];
  if (!empty_or_null(package_array['allowmaj'])) allowmaj = package_array['allowmaj'];
  if (!empty_or_null(package_array['exists_check'])) exists_check = package_array['exists_check'];
  if (!empty_or_null(package_array['cves'])) cves = package_array['cves'];
  if (reference && _release && (!exists_check || rpm_exists(release:_release, rpm:exists_check))) {
    if (rpm_check(release:_release, sp:sp, cpu:_cpu, reference:reference, epoch:epoch, el_string:el_string, rpm_spec_vers_cmp:rpm_spec_vers_cmp, allowmaj:allowmaj, cves:cves)) flag++;
  }
}

if (flag)
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_WARNING,
      extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  var tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "amazon-cloudwatch-agent");
}