CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
AV:N/AC:L/Au:N/C:P/I:P/A:P
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
Percentile
95.5%
The version of squid installed on the remote host is prior to 4.10-3. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2SQUID4-2023-007 advisory.
An issue was discovered in Squid before 4.9. When handling a URN request, a corresponding HTTP request is made. This HTTP request doesn’t go through the access checks that incoming HTTP requests go through. This causes all access checks to be bypassed and allows access to restricted HTTP servers, e.g., an attacker can connect to HTTP servers that only listen on localhost. (CVE-2019-12523)
An issue was discovered in Squid 3.3.9 through 3.5.28 and 4.x through 4.7. When Squid is configured to use Digest authentication, it parses the header Proxy-Authorization. It searches for certain tokens such as domain, uri, and qop. Squid checks if this token’s value starts with a quote and ends with one. If so, it performs a memcpy of its length minus 2. Squid never checks whether the value is just a single quote (which would satisfy its requirements), leading to a memcpy of its length minus 1. (CVE-2019-12525)
An issue was discovered in Squid before 4.9. URN response handling in Squid suffers from a heap-based buffer overflow. When receiving data from a remote server in response to an URN request, Squid fails to ensure that the response can fit within the buffer. This leads to attacker controlled data overflowing in the heap. (CVE-2019-12526)
An issue was discovered in Squid 3.x and 4.x through 4.8. Due to incorrect input validation, there is a heap-based buffer overflow that can result in Denial of Service to all clients using the proxy. Severity is high due to this vulnerability occurring before normal security checks; any remote client that can reach the proxy port can trivially perform the attack via a crafted URI scheme. (CVE-2019-18676)
An issue was discovered in Squid 3.x and 4.x through 4.8. It allows attackers to smuggle HTTP requests through frontend software to a Squid instance that splits the HTTP Request pipeline differently. The resulting Response messages corrupt caches (between a client and Squid) with attacker-controlled content at arbitrary URLs. Effects are isolated to software between the attacker client and Squid. There are no effects on Squid itself, nor on any upstream servers. The issue is related to a request header containing whitespace between a header name and a colon. (CVE-2019-18678)
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 ALASSQUID4-2023-007.
##
include('compat.inc');
if (description)
{
script_id(182047);
script_version("1.0");
script_set_attribute(attribute:"plugin_modification_date", value:"2023/09/27");
script_cve_id(
"CVE-2019-12523",
"CVE-2019-12525",
"CVE-2019-12526",
"CVE-2019-18676",
"CVE-2019-18678"
);
script_name(english:"Amazon Linux 2 : squid (ALASSQUID4-2023-007)");
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 4.10-3. It is, therefore, affected by multiple
vulnerabilities as referenced in the ALAS2SQUID4-2023-007 advisory.
- An issue was discovered in Squid before 4.9. When handling a URN request, a corresponding HTTP request is
made. This HTTP request doesn't go through the access checks that incoming HTTP requests go through. This
causes all access checks to be bypassed and allows access to restricted HTTP servers, e.g., an attacker
can connect to HTTP servers that only listen on localhost. (CVE-2019-12523)
- An issue was discovered in Squid 3.3.9 through 3.5.28 and 4.x through 4.7. When Squid is configured to use
Digest authentication, it parses the header Proxy-Authorization. It searches for certain tokens such as
domain, uri, and qop. Squid checks if this token's value starts with a quote and ends with one. If so, it
performs a memcpy of its length minus 2. Squid never checks whether the value is just a single quote
(which would satisfy its requirements), leading to a memcpy of its length minus 1. (CVE-2019-12525)
- An issue was discovered in Squid before 4.9. URN response handling in Squid suffers from a heap-based
buffer overflow. When receiving data from a remote server in response to an URN request, Squid fails to
ensure that the response can fit within the buffer. This leads to attacker controlled data overflowing in
the heap. (CVE-2019-12526)
- An issue was discovered in Squid 3.x and 4.x through 4.8. Due to incorrect input validation, there is a
heap-based buffer overflow that can result in Denial of Service to all clients using the proxy. Severity
is high due to this vulnerability occurring before normal security checks; any remote client that can
reach the proxy port can trivially perform the attack via a crafted URI scheme. (CVE-2019-18676)
- An issue was discovered in Squid 3.x and 4.x through 4.8. It allows attackers to smuggle HTTP requests
through frontend software to a Squid instance that splits the HTTP Request pipeline differently. The
resulting Response messages corrupt caches (between a client and Squid) with attacker-controlled content
at arbitrary URLs. Effects are isolated to software between the attacker client and Squid. There are no
effects on Squid itself, nor on any upstream servers. The issue is related to a request header containing
whitespace between a header name and a colon. (CVE-2019-18678)
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/ALASSQUID4-2023-007.html");
script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2019-12523.html");
script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2019-12525.html");
script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2019-12526.html");
script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2019-18676.html");
script_set_attribute(attribute:"see_also", value:"https://alas.aws.amazon.com/cve/html/CVE-2019-18678.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:N/C:P/I:P/A:P");
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:H/I:H/A:H");
script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
script_set_attribute(attribute:"cvss_score_source", value:"CVE-2019-12526");
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:"2019/07/11");
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_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-4.10-3.amzn2.0.1', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'squid4'},
{'reference':'squid-4.10-3.amzn2.0.1', 'cpu':'x86_64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'squid4'},
{'reference':'squid-debuginfo-4.10-3.amzn2.0.1', 'cpu':'aarch64', 'release':'AL2', 'rpm_spec_vers_cmp':TRUE, 'exists_check':'squid4'},
{'reference':'squid-debuginfo-4.10-3.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_HOLE,
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-2019-12523
cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-12525
cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-12526
cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-18676
cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-18678
alas.aws.amazon.com/AL2/ALASSQUID4-2023-007.html
alas.aws.amazon.com/cve/html/CVE-2019-12523.html
alas.aws.amazon.com/cve/html/CVE-2019-12525.html
alas.aws.amazon.com/cve/html/CVE-2019-12526.html
alas.aws.amazon.com/cve/html/CVE-2019-18676.html
alas.aws.amazon.com/cve/html/CVE-2019-18678.html
alas.aws.amazon.com/faqs.html
CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
AV:N/AC:L/Au:N/C:P/I:P/A:P
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
Percentile
95.5%