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
AI Score
Confidence
Low
EPSS
Percentile
68.0%
The remote Fedora 37 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2023-fef2b8da32 advisory.
This flaw makes curl overflow a heap based buffer in the SOCKS5 proxy handshake. When curl is asked to pass along the host name to the SOCKS5 proxy to allow that to resolve the address instead of it getting done by curl itself, the maximum length that host name can be is 255 bytes. If the host name is detected to be longer, curl switches to local name resolving and instead passes on the resolved address only. Due to this bug, the local variable that means let the host resolve the name could get the wrong value during a slow SOCKS5 handshake, and contrary to the intention, copy the too long host name to the target buffer instead of copying just the resolved address there. The target buffer being a heap based buffer, and the host name coming from the URL that curl has been told to operate with. (CVE-2023-38545)
CVE-2023-38545 is a heap-based buffer overflow vulnerability in the SOCKS5 proxy handshake in libcurl and curl. When curl is given a hostname to pass along to a SOCKS5 proxy that is greater than 255 bytes in length, it will switch to local name resolution in order to resolve the address before passing it on to the SOCKS5 proxy. However, due to a bug introduced in 2020, this local name resolution could fail due to a slow SOCKS5 handshake, causing curl to pass on the hostname greater than 255 bytes in length into the target buffer, leading to a heap overflow. The advisory for CVE-2023-38545 gives an example exploitation scenario of a malicious HTTPS server redirecting to a specially crafted URL. While it might seem that an attacker would need to influence the slowness of the SOCKS5 handshake, the advisory states that server latency is likely slow enough to trigger this bug. (CVE-2023-38545)
This flaw allows an attacker to insert cookies at will into a running program using libcurl, if the specific series of conditions are met. libcurl performs transfers. In its API, an application creates easy handles that are the individual handles for single transfers. libcurl provides a function call that duplicates en easy handle called curl_easy_duphandle. If a transfer has cookies enabled when the handle is duplicated, the cookie-enable state is also cloned - but without cloning the actual cookies. If the source handle did not read any cookies from a specific file on disk, the cloned version of the handle would instead store the file name as none
(using the four ASCII letters, no quotes). Subsequent use of the cloned handle that does not explicitly set a source to load cookies from would then inadvertently load cookies from a file named none
- if such a file exists and is readable in the current directory of the program using libcurl. And if using the correct file format of course.
(CVE-2023-38546)
CVE-2023-38546 is a cookie injection vulnerability in the curl_easy_duphandle(), a function in libcurl that duplicates easy handles. When duplicating an easy handle, if cookies are enabled, the duplicated easy handle will not duplicate the cookies themselves, but would instead set the filename to none.’ Therefore, when the duplicated easy handle is subsequently used, if a source was not set for the cookies, libcurl would attempt to load them from the file named none’ on the disk. This vulnerability is rated low, as the various conditions required for exploitation are unlikely. (CVE-2023-38546)
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 Fedora Security Advisory FEDORA-2023-fef2b8da32
#
include('compat.inc');
if (description)
{
script_id(183980);
script_version("1.3");
script_set_attribute(attribute:"plugin_modification_date", value:"2023/12/08");
script_cve_id("CVE-2023-38545", "CVE-2023-38546");
script_xref(name:"FEDORA", value:"2023-fef2b8da32");
script_xref(name:"CEA-ID", value:"CEA-2023-0052");
script_xref(name:"IAVA", value:"2023-A-0531-S");
script_name(english:"Fedora 37 : curl (2023-fef2b8da32)");
script_set_attribute(attribute:"synopsis", value:
"The remote Fedora host is missing one or more security updates.");
script_set_attribute(attribute:"description", value:
"The remote Fedora 37 host has a package installed that is affected by multiple vulnerabilities as referenced in the
FEDORA-2023-fef2b8da32 advisory.
- This flaw makes curl overflow a heap based buffer in the SOCKS5 proxy handshake. When curl is asked to
pass along the host name to the SOCKS5 proxy to allow that to resolve the address instead of it getting
done by curl itself, the maximum length that host name can be is 255 bytes. If the host name is detected
to be longer, curl switches to local name resolving and instead passes on the resolved address only. Due
to this bug, the local variable that means let the host resolve the name could get the wrong value
during a slow SOCKS5 handshake, and contrary to the intention, copy the too long host name to the target
buffer instead of copying just the resolved address there. The target buffer being a heap based buffer,
and the host name coming from the URL that curl has been told to operate with. (CVE-2023-38545)
- CVE-2023-38545 is a heap-based buffer overflow vulnerability in the SOCKS5 proxy handshake in libcurl and
curl. When curl is given a hostname to pass along to a SOCKS5 proxy that is greater than 255 bytes in
length, it will switch to local name resolution in order to resolve the address before passing it on to
the SOCKS5 proxy. However, due to a bug introduced in 2020, this local name resolution could fail due to a
slow SOCKS5 handshake, causing curl to pass on the hostname greater than 255 bytes in length into the
target buffer, leading to a heap overflow. The advisory for CVE-2023-38545 gives an example exploitation
scenario of a malicious HTTPS server redirecting to a specially crafted URL. While it might seem that an
attacker would need to influence the slowness of the SOCKS5 handshake, the advisory states that server
latency is likely slow enough to trigger this bug. (CVE-2023-38545)
- This flaw allows an attacker to insert cookies at will into a running program using libcurl, if the
specific series of conditions are met. libcurl performs transfers. In its API, an application creates
easy handles that are the individual handles for single transfers. libcurl provides a function call that
duplicates en easy handle called
[curl_easy_duphandle](https://curl.se/libcurl/c/curl_easy_duphandle.html). If a transfer has cookies
enabled when the handle is duplicated, the cookie-enable state is also cloned - but without cloning the
actual cookies. If the source handle did not read any cookies from a specific file on disk, the cloned
version of the handle would instead store the file name as `none` (using the four ASCII letters, no
quotes). Subsequent use of the cloned handle that does not explicitly set a source to load cookies from
would then inadvertently load cookies from a file named `none` - if such a file exists and is readable in
the current directory of the program using libcurl. And if using the correct file format of course.
(CVE-2023-38546)
- CVE-2023-38546 is a cookie injection vulnerability in the curl_easy_duphandle(), a function in libcurl
that duplicates easy handles. When duplicating an easy handle, if cookies are enabled, the duplicated
easy handle will not duplicate the cookies themselves, but would instead set the filename to none.'
Therefore, when the duplicated easy handle is subsequently used, if a source was not set for the cookies,
libcurl would attempt to load them from the file named none' on the disk. This vulnerability is rated
low, as the various conditions required for exploitation are unlikely. (CVE-2023-38546)
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://bodhi.fedoraproject.org/updates/FEDORA-2023-fef2b8da32");
script_set_attribute(attribute:"solution", value:
"Update the affected curl package.");
script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C");
script_set_cvss_temporal_vector("CVSS2#E:POC/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:P/RL:O/RC:C");
script_set_attribute(attribute:"cvss_score_source", value:"CVE-2023-38545");
script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
script_set_attribute(attribute:"exploit_available", value:"true");
script_set_attribute(attribute:"vuln_publication_date", value:"2023/10/10");
script_set_attribute(attribute:"patch_publication_date", value:"2023/10/12");
script_set_attribute(attribute:"plugin_publication_date", value:"2023/10/27");
script_set_attribute(attribute:"plugin_type", value:"local");
script_set_attribute(attribute:"cpe", value:"cpe:/o:fedoraproject:fedora:37");
script_set_attribute(attribute:"cpe", value:"p-cpe:/a:fedoraproject:fedora:curl");
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:"Fedora 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/RedHat/release", "Host/RedHat/rpm-list");
exit(0);
}
include('rpm.inc');
if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_release = get_kb_item('Host/RedHat/release');
if (isnull(os_release) || 'Fedora' >!< os_release) audit(AUDIT_OS_NOT, 'Fedora');
var os_ver = pregmatch(pattern: "Fedora.*release ([0-9]+)", string:os_release);
if (isnull(os_ver)) audit(AUDIT_UNKNOWN_APP_VER, 'Fedora');
os_ver = os_ver[1];
if (! preg(pattern:"^37([^0-9]|$)", string:os_ver)) audit(AUDIT_OS_NOT, 'Fedora 37', 'Fedora ' + os_ver);
if (!get_kb_item('Host/RedHat/rpm-list')) audit(AUDIT_PACKAGE_LIST_MISSING);
var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('x86_64' >!< cpu && cpu !~ "^i[3-6]86$" && 's390' >!< cpu && 'aarch64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'Fedora', cpu);
var pkgs = [
{'reference':'curl-7.85.0-12.fc37', 'release':'FC37', 'rpm_spec_vers_cmp':TRUE}
];
var flag = 0;
foreach 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;
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 (reference && _release) {
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, 'curl');
}
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
AI Score
Confidence
Low
EPSS
Percentile
68.0%