CVSS2
Attack Vector
NETWORK
Attack Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:N/AC:M/Au:N/C:N/I:P/A:N
EPSS
Percentile
98.4%
According to its SIP banner, the version of Asterisk running on the remote host is potentially affected by flaw related to certificate validation when registering a SIP TLS device due to not properly verifying a server hostname against an X.509 Common Name (CN) field that has a NULL byte appended after the expected results. A man-in-the-middle attacker can exploit this, via a crafted certificate, to spoof arbitrary SSL servers and intercept network traffic.
Note that Nessus has not tested for this issue but has instead relied only on the application’s self-reported version number.
#%NASL_MIN_LEVEL 70300
#
# (C) Tenable Network Security, Inc.
#
include('deprecated_nasl_level.inc');
include('compat.inc');
if (description)
{
script_id(82901);
script_version("1.10");
script_set_attribute(attribute:"plugin_modification_date", value:"2022/04/11");
script_cve_id("CVE-2015-3008");
script_bugtraq_id(74022);
script_name(english:"Asterisk TLS Certificate Common Name NULL Byte Vulnerability (AST-2015-003)");
script_set_attribute(attribute:"synopsis", value:
"A telephony application running on the remote host is affected by a
certificate validation vulnerability.");
script_set_attribute(attribute:"description", value:
"According to its SIP banner, the version of Asterisk running on the
remote host is potentially affected by flaw related to certificate
validation when registering a SIP TLS device due to not properly
verifying a server hostname against an X.509 Common Name (CN) field
that has a NULL byte appended after the expected results. A
man-in-the-middle attacker can exploit this, via a crafted
certificate, to spoof arbitrary SSL servers and intercept network
traffic.
Note that Nessus has not tested for this issue but has instead relied
only on the application's self-reported version number.");
script_set_attribute(attribute:"see_also", value:"http://downloads.asterisk.org/pub/security/AST-2015-003.html");
script_set_attribute(attribute:"see_also", value:"https://issues.asterisk.org/jira/browse/ASTERISK-24847");
script_set_attribute(attribute:"solution", value:
"Upgrade to Asterisk 1.8.32.3 / 11.17.1 / 12.8.2 / 13.3.2 /
1.8.28-cert5 / 11.6-cert11 / 13.1-cert2, or apply the appropriate
patch listed in the Asterisk advisory.");
script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:N/I:P/A:N");
script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
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:"2015/04/08");
script_set_attribute(attribute:"patch_publication_date", value:"2015/04/08");
script_set_attribute(attribute:"plugin_publication_date", value:"2015/04/20");
script_set_attribute(attribute:"potential_vulnerability", value:"true");
script_set_attribute(attribute:"plugin_type", value:"remote");
script_set_attribute(attribute:"cpe", value:"cpe:/a:digium:asterisk");
script_set_attribute(attribute:"thorough_tests", value:"true");
script_end_attributes();
script_category(ACT_GATHER_INFO);
script_family(english:"Misc.");
script_copyright(english:"This script is Copyright (C) 2015-2022 Tenable Network Security, Inc.");
script_dependencies("asterisk_detection.nasl");
script_require_keys("asterisk/sip_detected", "Settings/ParanoidReport");
exit(0);
}
include("audit.inc");
include("global_settings.inc");
include("misc_func.inc");
get_kb_item_or_exit("asterisk/sip_detected");
asterisk_kbs = get_kb_list_or_exit("sip/asterisk/*/version");
if (report_paranoia < 2) audit(AUDIT_PARANOID);
is_vuln = FALSE;
not_vuln_installs = make_list();
errors = make_list();
foreach kb_name (keys(asterisk_kbs))
{
vulnerable = 0;
matches = eregmatch(pattern:"/(udp|tcp)/([0-9]+)/version", string:kb_name);
if (isnull(matches))
{
errors = make_list(errors, "Unexpected error parsing port number from '"+kb_name+"'.");
continue;
}
proto = matches[1];
port = matches[2];
version = asterisk_kbs[kb_name];
if (version == 'unknown')
{
errors = make_list(errors, "Unable to obtain version of install on " + proto + "/" + port + ".");
continue;
}
banner = get_kb_item("sip/asterisk/" + proto + "/" + port + "/source");
if (!banner)
{
# We have version but banner is missing;
# log error and use in version-check though.
errors = make_list(errors, "KB item 'sip/asterisk/" + proto + "/" + port + "/source' is missing.");
banner = 'unknown';
}
# Open Source 1.8.x < 1.8.32.3
if (version =~ "^1\.8([^0-9]|$)" && "cert" >!< tolower(version))
{
fixed = "1.8.32.3";
vulnerable = ver_compare(ver:version, fix:fixed, app:"asterisk");
}
# Open Source 11.x < 11.17.1
if (version =~ "^11([^0-9]|$)" && "cert" >!< tolower(version))
{
fixed = "11.17.1";
vulnerable = ver_compare(ver:version, fix:fixed, app:"asterisk");
}
# Open Source 12.x < 12.8.2
else if (version =~ "^12([^0-9]|$)" && "cert" >!< tolower(version))
{
fixed = "12.8.2";
vulnerable = ver_compare(ver:version, fix:fixed, app:"asterisk");
}
# Open Source 13.x < 13.3.2
else if (version =~ "^13([^0-9]|$)" && "cert" >!< tolower(version))
{
fixed = "13.3.2";
vulnerable = ver_compare(ver:version, fix:fixed, app:"asterisk");
}
# Asterisk Certified 1.8.28-certx < 1.8.28-cert5
else if (version =~ "^1\.8\.28([^0-9])" && "cert" >< tolower(version))
{
fixed = "1.8.28-cert5";
vulnerable = ver_compare(ver:version, fix:fixed, app:"asterisk");
}
# Asterisk Certified 11.6-certx < 11.6-cert11
else if (version =~ "^11\.6([^0-9])" && "cert" >< tolower(version))
{
fixed = "11.6-cert11";
vulnerable = ver_compare(ver:version, fix:fixed, app:"asterisk");
}
# Asterisk Certified 13.1-certx < 13.1-cert2
else if (version =~ "^13\.1([^0-9])" && "cert" >< tolower(version))
{
fixed = "13.1-cert2";
vulnerable = ver_compare(ver:version, fix:fixed, app:"asterisk");
}
if (vulnerable < 0)
{
is_vuln = TRUE;
if (report_verbosity > 0)
{
report =
'\n Version source : ' + banner +
'\n Installed version : ' + version +
'\n Fixed version : ' + fixed +
'\n';
security_warning(port:port, proto:proto, extra:report);
}
else security_warning(port:port, proto:proto);
}
else not_vuln_installs = make_list(not_vuln_installs, version + " on port " + proto + "/" + port);
}
if (max_index(errors))
{
if (max_index(errors) == 1) errmsg = errors[0];
else errmsg = 'Errors were encountered verifying installs : \n ' + join(errors, sep:'\n ');
exit(1, errmsg);
}
else
{
installs = max_index(not_vuln_installs);
if (installs == 0)
{
if (is_vuln) exit(0);
else audit(AUDIT_NOT_INST, "Asterisk");
}
else audit(AUDIT_INST_VER_NOT_VULN, "Asterisk", not_vuln_installs);
}