Vulnerabilities > CVE-2018-4241 - Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability in Apple products

047910
CVSS 9.3 - CRITICAL
Attack vector
NETWORK
Attack complexity
MEDIUM
Privileges required
NONE
Confidentiality impact
COMPLETE
Integrity impact
COMPLETE
Availability impact
COMPLETE
network
apple
CWE-119
critical
nessus
exploit available
NVD
Published: 2018-06-08
Updated: 2018-07-17

Summary

An issue was discovered in certain Apple products. iOS before 11.4 is affected. macOS before 10.13.5 is affected. tvOS before 11.4 is affected. watchOS before 4.3.1 is affected. The issue involves the "Kernel" component. A buffer overflow in mptcp_usr_connectx allows attackers to execute arbitrary code in a privileged context via a crafted app.

Vulnerable Configurations

Part Description Count
Application
Apple
57
OS
Apple
306

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Buffer Overflow via Environment Variables
    This attack pattern involves causing a buffer overflow through manipulation of environment variables. Once the attacker finds that they can modify an environment variable, they may try to overflow associated buffers. This attack leverages implicit trust often placed in environment variables.
  • Overflow Buffers
    Buffer Overflow attacks target improper or missing bounds checking on buffer operations, typically triggered by input injected by an attacker. As a consequence, an attacker is able to write past the boundaries of allocated buffer regions in memory, causing a program crash or potentially redirection of execution as per the attackers' choice.
  • Client-side Injection-induced Buffer Overflow
    This type of attack exploits a buffer overflow vulnerability in targeted client software through injection of malicious content from a custom-built hostile service.
  • Filter Failure through Buffer Overflow
    In this attack, the idea is to cause an active filter to fail by causing an oversized transaction. An attacker may try to feed overly long input strings to the program in an attempt to overwhelm the filter (by causing a buffer overflow) and hoping that the filter does not fail securely (i.e. the user input is let into the system unfiltered).
  • MIME Conversion
    An attacker exploits a weakness in the MIME conversion routine to cause a buffer overflow and gain control over the mail server machine. The MIME system is designed to allow various different information formats to be interpreted and sent via e-mail. Attack points exist when data are converted to MIME compatible format and back.

Exploit-Db

descriptionXNU Kernel - Heap Overflow Due to Bad Bounds Checking in MPTCP. CVE-2018-4241. Dos exploit for Multiple platform. Tags: Heap Overflow
fileexploits/multiple/dos/44849.txt
idEDB-ID:44849
last seen2018-06-06
modified2018-06-06
platformmultiple
port
published2018-06-06
reporterExploit-DB
sourcehttps://www.exploit-db.com/download/44849/
titleXNU Kernel - Heap Overflow Due to Bad Bounds Checking in MPTCP
typedos

Nessus

  • NASL familyMisc.
    NASL idAPPLETV_11_4.NASL
    descriptionAccording to its banner, the version of Apple TV on the remote device is prior to 11.4. It is, therefore, affected by multiple vulnerabilities as described in the HT208850 security advisory. Note that only 4th and 5th generation models are affected by these vulnerabilities.
    last seen2020-06-01
    modified2020-06-02
    plugin id110325
    published2018-06-05
    reporterThis script is Copyright (C) 2018-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/110325
    titleApple TV < 11.4 Multiple Vulnerabilities
    code
    #
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(110325);
  script_version("1.6");
  script_cvs_date("Date: 2019/04/05 23:25:06");

  script_cve_id(
    "CVE-2018-4188",
    "CVE-2018-4190",
    "CVE-2018-4192",
    "CVE-2018-4198",
    "CVE-2018-4199",
    "CVE-2018-4200",
    "CVE-2018-4201",
    "CVE-2018-4204",
    "CVE-2018-4206",
    "CVE-2018-4211",
    "CVE-2018-4214",
    "CVE-2018-4218",
    "CVE-2018-4222",
    "CVE-2018-4223",
    "CVE-2018-4224",
    "CVE-2018-4232",
    "CVE-2018-4233",
    "CVE-2018-4235",
    "CVE-2018-4237",
    "CVE-2018-4240",
    "CVE-2018-4241",
    "CVE-2018-4243",
    "CVE-2018-4246",
    "CVE-2018-4249",
    "CVE-2018-5383"
  );
  script_bugtraq_id(
    103957,
    103958,
    103961,
    104378
  );
  script_xref(name:"APPLE-SA", value:"APPLE-SA-2018-6-01-6");

  script_name(english:"Apple TV < 11.4 Multiple Vulnerabilities");
  script_summary(english:"Checks the build number.");

  script_set_attribute(attribute:"synopsis", value:
"The remote Apple TV device is affected by multiple vulnerabilities.");
  script_set_attribute(attribute:"description", value:
"According to its banner, the version of Apple TV on the remote device
is prior to 11.4. It is, therefore, affected by multiple
vulnerabilities as described in the HT208850 security advisory.

Note that only 4th and 5th generation models are affected by these
vulnerabilities.");
  script_set_attribute(attribute:"see_also", value:"https://support.apple.com/en-us/HT208850");
  # https://lists.apple.com/archives/security-announce/2018/Jun/msg00003.html
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?0e8b8fb7");
  # https://lists.apple.com/archives/security-announce/2018/Jul/msg00011.html
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?b0bb7d4f");
  script_set_attribute(attribute:"solution", value:
"Upgrade to Apple TV version 11.4 or later. Note that this update is
only available for 4th and 5th generation models.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:M/Au:N/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:H/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:H/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2018-4241");
  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"exploited_by_malware", value:"true");
  script_set_attribute(attribute:"metasploit_name", value:'Mac OS X libxpc MITM Privilege Escalation');
  script_set_attribute(attribute:"exploit_framework_metasploit", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2018/06/01");
  script_set_attribute(attribute:"patch_publication_date", value:"2018/06/01");
  script_set_attribute(attribute:"plugin_publication_date", value:"2018/06/05");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/a:apple:apple_tv");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Misc.");

  script_copyright(english:"This script is Copyright (C) 2018-2019 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("appletv_version.nasl");
  script_require_keys("AppleTV/Version", "AppleTV/Model", "AppleTV/URL", "AppleTV/Port");
  script_require_ports("Services/www", 7000);

  exit(0);
}

include("audit.inc");
include("appletv_func.inc");

url = get_kb_item('AppleTV/URL');
if (empty_or_null(url)) exit(0, 'Cannot determine Apple TV URL.');
port = get_kb_item('AppleTV/Port');
if (empty_or_null(port)) exit(0, 'Cannot determine Apple TV port.');

build = get_kb_item('AppleTV/Version');
if (empty_or_null(build)) audit(AUDIT_UNKNOWN_DEVICE_VER, 'Apple TV');

model = get_kb_item('AppleTV/Model');
if (empty_or_null(model)) exit(0, 'Cannot determine Apple TV model.');

# https://en.wikipedia.org/wiki/TvOS
# 4th gen model "5,3" and 5th gen model "6,2" share same build
fixed_build = "15L577";
tvos_ver = '11';

# determine gen from the model
gen = APPLETV_MODEL_GEN[model];

appletv_check_version(
  build          : build,
  fix            : fixed_build,
  affected_gen   : make_list(4, 5),
  fix_tvos_ver   : tvos_ver,
  model          : model,
  gen            : gen,
  port           : port,
  url            : url,
  severity       : SECURITY_HOLE
);
  • NASL familyMacOS X Local Security Checks
    NASL idMACOS_10_13_5.NASL
    descriptionThe remote host is running a version of macOS / Mac OS X that is 10.13.x prior to 10.13.5. It is, therefore, affected by multiple vulnerabilities. Note that successful exploitation of the most serious issues can result in arbitrary code execution.
    last seen2020-06-01
    modified2020-06-02
    plugin id110324
    published2018-06-05
    reporterThis script is Copyright (C) 2018-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
    sourcehttps://www.tenable.com/plugins/nessus/110324
    titlemacOS 10.13.x < 10.13.5 Multiple Vulnerabilities
    code
    #
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(110324);
  script_version("1.11");
  script_cvs_date("Date: 2019/11/04");

  script_cve_id(
    "CVE-2018-4141",
    "CVE-2018-4159",
    "CVE-2018-4180",
    "CVE-2018-4181",
    "CVE-2018-4182",
    "CVE-2018-4183",
    "CVE-2018-4184",
    "CVE-2018-4193",
    "CVE-2018-4194",
    "CVE-2018-4196",
    "CVE-2018-4198",
    "CVE-2018-4202",
    "CVE-2018-4211",
    "CVE-2018-4217",
    "CVE-2018-4219",
    "CVE-2018-4221",
    "CVE-2018-4223",
    "CVE-2018-4224",
    "CVE-2018-4225",
    "CVE-2018-4226",
    "CVE-2018-4227",
    "CVE-2018-4228",
    "CVE-2018-4229",
    "CVE-2018-4230",
    "CVE-2018-4234",
    "CVE-2018-4235",
    "CVE-2018-4236",
    "CVE-2018-4237",
    "CVE-2018-4240",
    "CVE-2018-4241",
    "CVE-2018-4242",
    "CVE-2018-4243",
    "CVE-2018-4249",
    "CVE-2018-4251",
    "CVE-2018-4253",
    "CVE-2018-4254",
    "CVE-2018-4255",
    "CVE-2018-4256",
    "CVE-2018-4257",
    "CVE-2018-4258",
    "CVE-2018-4404",
    "CVE-2018-4478",
    "CVE-2018-5383",
    "CVE-2018-7584"
  );
  script_bugtraq_id(
    103204,
    104378,
    104879,
    104888,
    104889,
    104897,
    107135
  );
  script_xref(name:"APPLE-SA", value:"APPLE-SA-2018-7-23-2");

  script_name(english:"macOS 10.13.x < 10.13.5 Multiple Vulnerabilities");
  script_summary(english:"Checks the version of Mac OS X / macOS.");

  script_set_attribute(attribute:"synopsis", value:
"The remote host is missing a macOS update that fixes multiple security
vulnerabilities.");
  script_set_attribute(attribute:"description", value:
"The remote host is running a version of macOS / Mac OS X that is
10.13.x prior to 10.13.5. It is, therefore, affected by multiple
vulnerabilities.

Note that successful exploitation of the most serious issues can
result in arbitrary code execution.");
  script_set_attribute(attribute:"see_also", value:"https://support.apple.com/en-us/HT208849");
  # https://lists.apple.com/archives/security-announce/2018/Jul/msg00009.html
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?68a789b4");
  script_set_attribute(attribute:"solution", value:
"Upgrade to macOS version 10.13.5 or later.");
  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:H/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:H/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2018-4258");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");
  script_set_attribute(attribute:"exploited_by_malware", value:"true");
  script_set_attribute(attribute:"metasploit_name", value:'Safari Proxy Object Type Confusion');
  script_set_attribute(attribute:"exploit_framework_metasploit", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2018/06/01");
  script_set_attribute(attribute:"patch_publication_date", value:"2018/06/01");
  script_set_attribute(attribute:"plugin_publication_date", value:"2018/06/05");

  script_set_attribute(attribute:"plugin_type", value:"combined");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:apple:mac_os_x");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:apple:macos");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"MacOS X Local Security Checks");

  script_copyright(english:"This script is Copyright (C) 2018-2019 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl", "os_fingerprint.nasl");
  script_require_ports("Host/MacOSX/Version", "Host/OS");

  exit(0);
}

include("audit.inc");
include("global_settings.inc");
include("misc_func.inc");

os = get_kb_item("Host/MacOSX/Version");
if (!os)
{
  os = get_kb_item_or_exit("Host/OS");
  if ("Mac OS X" >!< os) audit(AUDIT_OS_NOT, "macOS / Mac OS X");

  c = get_kb_item("Host/OS/Confidence");
  if (c <= 70) exit(1, "Can't determine the host's OS with sufficient confidence.");
}
if (!os) audit(AUDIT_OS_NOT, "macOS / Mac OS X");

matches = pregmatch(pattern:"Mac OS X ([0-9]+(\.[0-9]+)+)", string:os);
if (empty_or_null(matches)) exit(1, "Failed to parse the macOS / Mac OS X version ('" + os + "').");

version = matches[1];
fix = "10.13.5";

if (version !~"^10\.13($|[^0-9])")
  audit(AUDIT_OS_NOT, "macOS 10.13.x");

if (ver_compare(ver:version, fix:fix, strict:FALSE) == -1)
{
  security_report_v4(
    port:0,
    severity:SECURITY_HOLE,
    extra:
      '\n  Installed version : ' + version +
      '\n  Fixed version     : ' + fix +
      '\n'
  );
}
else audit(AUDIT_INST_VER_NOT_VULN, "macOS / Mac OS X", version);

Seebug

bulletinFamilyexploit
descriptionmptcp_usr_connectx is the handler for the connectx syscall for the AP_MULTIPATH socket family. The logic of this function fails to correctly handle source and destination sockaddrs which aren't AF_INET or AF_INET6: ``` // verify sa_len for AF_INET: if (dst->sa_family == AF_INET && dst->sa_len != sizeof(mpte->__mpte_dst_v4)) { mptcplog((LOG_ERR, "%s IPv4 dst len %u\n", __func__, dst->sa_len), MPTCP_SOCKET_DBG, MPTCP_LOGLVL_ERR); error = EINVAL; goto out; } // verify sa_len for AF_INET6: if (dst->sa_family == AF_INET6 && dst->sa_len != sizeof(mpte->__mpte_dst_v6)) { mptcplog((LOG_ERR, "%s IPv6 dst len %u\n", __func__, dst->sa_len), MPTCP_SOCKET_DBG, MPTCP_LOGLVL_ERR); error = EINVAL; goto out; } // code doesn't bail if sa_family was neither AF_INET nor AF_INET6 if (!(mpte->mpte_flags & MPTE_SVCTYPE_CHECKED)) { if (mptcp_entitlement_check(mp_so) < 0) { error = EPERM; goto out; } mpte->mpte_flags |= MPTE_SVCTYPE_CHECKED; } // memcpy with sa_len up to 255: if ((mp_so->so_state & (SS_ISCONNECTED|SS_ISCONNECTING)) == 0) { memcpy(&mpte->mpte_dst, dst, dst->sa_len); } ``` This PoC triggers the issue to overwrite the mpte_itfinfo field leading to a controlled pointer being passed to kfree when the socket is closed. Please note that these lengths seem to be trusted in multiple places - I would strongly suggest auditing this code quite thoroughly, especially as mptcp can be reached from more places as of iOS 11. Note that the MPTCP code does seem to be quite buggy; trying to get a nice PoC working for this buffer overflow bug I accidentally triggered the following error path: ``` error = socreate_internal(dom, so, SOCK_STREAM, IPPROTO_TCP, p, SOCF_ASYNC, PROC_NULL); mpte_lock(mpte); if (error) { mptcplog((LOG_ERR, "%s: subflow socreate mp_so 0x%llx unable to create subflow socket error %d\n", (u_int64_t)VM_KERNEL_ADDRPERM(mp_so), error), MPTCP_SOCKET_DBG, MPTCP_LOGLVL_ERR); proc_rele(p); mptcp_subflow_free(mpts); return (error); } ``` note that first argument to mptcplog has one too few arguments. It's probably not so interesting from a security POV but is indicative of untested code (this error path has clearly never run as it will always kernel panic.) This PoC is for MacOS but note that this code is reachable on iOS 11 from inside the app sandbox if you give yourself the multipath entitlement (which app store apps can now use.) Just run this PoC as root on MacOS for easy repro.
idSSV:97338
last seen2018-06-10
modified2018-06-08
published2018-06-08
reporterKnownsec
sourcehttps://www.seebug.org/vuldb/ssvid-97338
titleXNU kernel heap overflow due to bad bounds checking in MPTCP(CVE-2018-4241)

References