CVSS2
Attack Vector
NETWORK
Attack Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
COMPLETE
AV:N/AC:M/Au:N/C:N/I:N/A:C
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
EPSS
Percentile
86.8%
The version of squid installed on the remote host is prior to 4.13-1. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2SQUID4-2023-006 advisory.
An issue was discovered in Squid before 4.13 and 5.x before 5.0.4. Due to incorrect data validation, HTTP Request Smuggling attacks may succeed against HTTP and HTTPS traffic. This leads to cache poisoning. This allows any client, including browser scripts, to bypass local security and poison the proxy cache and any downstream caches with content from an arbitrary source. When configured for relaxed header parsing (the default), Squid relays headers containing whitespace characters to upstream servers. When this occurs as a prefix to a Content-Length header, the frame length specified will be ignored by Squid (allowing for a conflicting length to be used from another Content-Length header) but relayed upstream. (CVE-2020-15810)
An issue was discovered in Squid before 4.13 and 5.x before 5.0.4. Due to incorrect data validation, HTTP Request Splitting attacks may succeed against HTTP and HTTPS traffic. This leads to cache poisoning. This allows any client, including browser scripts, to bypass local security and poison the browser cache and any downstream caches with content from an arbitrary source. Squid uses a string search instead of parsing the Transfer-Encoding header to find chunked encoding. This allows an attacker to hide a second request inside Transfer-Encoding: it is interpreted by Squid as chunked and split out into a second request delivered upstream. Squid will then deliver two distinct responses to the client, corrupting any downstream caches. (CVE-2020-15811)
Squid before 4.13 and 5.x before 5.0.4 allows a trusted peer to perform Denial of Service by consuming all available CPU cycles during handling of a crafted Cache Digest response message. This only occurs when cache_peer is used with the cache digests feature. The problem exists because peerDigestHandleReply() livelocking in peer_digest.cc mishandles EOF. (CVE-2020-24606)
Note that Nessus has not tested for these issues but has instead relied only on the application’s self-reported version number.
#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
#
# The descriptive text and package checks in this plugin were
# extracted from Amazon Linux 2 Security Advisory ALASSQUID4-2023-006.
##
include('compat.inc');
if (description)
{
script_id(181961);
script_version("1.0");
script_set_attribute(attribute:"plugin_modification_date", value:"2023/09/27");
script_cve_id("CVE-2020-15810", "CVE-2020-15811", "CVE-2020-24606");
script_xref(name:"IAVB", value:"2020-B-0050-S");
script_name(english:"Amazon Linux 2 : squid (ALASSQUID4-2023-006)");
script_set_attribute(attribute:"synopsis", value:
"The remote Amazon Linux 2 host is missing a security update.");
script_set_attribute(attribute:"description", value:
"The version of squid installed on the remote host is prior to 4.13-1. It is, therefore, affected by multiple
vulnerabilities as referenced in the ALAS2SQUID4-2023-006 advisory.
- An issue was discovered in Squid before 4.13 and 5.x before 5.0.4. Due to incorrect data validation, HTTP
Request Smuggling attacks may succeed against HTTP and HTTPS traffic. This leads to cache poisoning. This
allows any client, including browser scripts, to bypass local security and poison the proxy cache and any
downstream caches with content from an arbitrary source. When configured for relaxed header parsing (the
default), Squid relays headers containing whitespace characters to upstream servers. When this occurs as a
prefix to a Content-Length header, the frame length specified will be ignored by Squid (allowing for a
conflicting length to be used from another Content-Length header) but relayed upstream. (CVE-2020-15810)
- An issue was discovered in Squid before 4.13 and 5.x before 5.0.4. Due to incorrect data validation, HTTP
Request Splitting attacks may succeed against HTTP and HTTPS traffic. This leads to cache poisoning. This
allows any client, including browser scripts, to bypass local security and poison the browser cache and
any downstream caches with content from an arbitrary source. Squid uses a string search instead of parsing
the Transfer-Encoding header to find chunked encoding. This allows an attacker to hide a second request
inside Transfer-Encoding: it is interpreted by Squid as chunked and split out into a second request
delivered upstream. Squid will then deliver two distinct responses to the client, corrupting any
downstream caches. (CVE-2020-15811)
- Squid before 4.13 and 5.x before 5.0.4 allows a trusted peer to perform Denial of Service by consuming all
available CPU cycles during handling of a crafted Cache Digest response message. This only occurs when
cache_peer is used with the cache digests feature. The problem exists because peerDigestHandleReply()
livelocking in peer_digest.cc mishandles EOF. (CVE-2020-24606)
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/AL2/ALASSQUID4-2023-006.html");
script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2020-15810.html");
script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2020-15811.html");
script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2020-24606.html");
script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/faqs.html");
script_set_attribute(attribute:"solution", value:
"Run 'yum update squid' to update your system.");
script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/C:N/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:L/UI:N/S:U/C:N/I:H/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-2020-15811");
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:"2020/08/24");
script_set_attribute(attribute:"patch_publication_date", value:"2023/08/21");
script_set_attribute(attribute:"plugin_publication_date", value:"2023/09/27");
script_set_attribute(attribute:"plugin_type", value:"local");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:squid");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:amazon:linux:squid-debuginfo");
script_set_attribute(attribute:"cpe", value:"cpe:/o:amazon:linux:2");
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) 2023 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 != "2")
{
if (os_ver == 'A') os_ver = 'AMI';
audit(AUDIT_OS_NOT, "Amazon Linux 2", "Amazon Linux " + os_ver);
}
if (!get_kb_item("Host/AmazonLinux/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);
var pkgs = [
{'reference':'squid-4.13-1.amzn2.0.1', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'squid4'},
{'reference':'squid-4.13-1.amzn2.0.1', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'squid4'},
{'reference':'squid-debuginfo-4.13-1.amzn2.0.1', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'squid4'},
{'reference':'squid-debuginfo-4.13-1.amzn2.0.1', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'squid4'}
];
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;
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 (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)) 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, "squid / squid-debuginfo");
}
cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-15810
cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-15811
cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-24606
alas.aws.amazon.com/AL2/ALASSQUID4-2023-006.html
alas.aws.amazon.com/cve/html/CVE-2020-15810.html
alas.aws.amazon.com/cve/html/CVE-2020-15811.html
alas.aws.amazon.com/cve/html/CVE-2020-24606.html
alas.aws.amazon.com/faqs.html
CVSS2
Attack Vector
NETWORK
Attack Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
COMPLETE
AV:N/AC:M/Au:N/C:N/I:N/A:C
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
EPSS
Percentile
86.8%