EulerOS 2.0 SP1 : curl (EulerOS-SA-2017-1287)

2017-12-01T00:00:00
ID EULEROS_SA-2017-1287.NASL
Type nessus
Reporter Tenable
Modified 2018-11-14T00:00:00

Description

According to the version of the curl packages installed, the EulerOS installation on the remote host is affected by the following vulnerability :

  • libcurl may read outside of a heap allocated buffer when doing FTP. When libcurl connects to an FTP server and successfully logs in (anonymous or not), it asks the server for the current directory with the PWD command. The server then responds with a 257 response containing the path, inside double quotes. The returned path name is then kept by libcurl for subsequent uses. Due to a flaw in the string parser for this directory name, a directory name passed like this but without a closing double quote would lead to libcurl not adding a trailing NUL byte to the buffer holding the name. When libcurl would then later access the string, it could read beyond the allocated heap buffer and crash or wrongly access data beyond the buffer, thinking it was part of the path. A malicious server could abuse this fact and effectively prevent libcurl-based clients to work with it - the PWD command is always issued on new FTP connections and the mistake has a high chance of causing a segfault. The simple fact that this has issue remained undiscovered for this long could suggest that malformed PWD responses are rare in benign servers. We are not aware of any exploit of this flaw. This bug was introduced in commit 415d2e7cb7, March 2005. In libcurl version 7.56.0, the parser always zero terminates the string but also rejects it if not terminated properly with a final double quote.(CVE-2017-1000254)

Note that Tenable Network Security has extracted the preceding description block directly from the EulerOS security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

                                        
                                            #
# (C) Tenable Network Security, Inc.
#

include("compat.inc");

if (description)
{
  script_id(104906);
  script_version("3.8");
  script_cvs_date("Date: 2018/11/14 14:36:23");

  script_cve_id(
    "CVE-2017-1000254"
  );

  script_name(english:"EulerOS 2.0 SP1 : curl (EulerOS-SA-2017-1287)");
  script_summary(english:"Checks the rpm output for the updated package.");

  script_set_attribute(attribute:"synopsis", value:
"The remote EulerOS host is missing a security update.");
  script_set_attribute(attribute:"description", value:
"According to the version of the curl packages installed, the EulerOS
installation on the remote host is affected by the following
vulnerability :

  - libcurl may read outside of a heap allocated buffer
    when doing FTP. When libcurl connects to an FTP server
    and successfully logs in (anonymous or not), it asks
    the server for the current directory with the `PWD`
    command. The server then responds with a 257 response
    containing the path, inside double quotes. The returned
    path name is then kept by libcurl for subsequent uses.
    Due to a flaw in the string parser for this directory
    name, a directory name passed like this but without a
    closing double quote would lead to libcurl not adding a
    trailing NUL byte to the buffer holding the name. When
    libcurl would then later access the string, it could
    read beyond the allocated heap buffer and crash or
    wrongly access data beyond the buffer, thinking it was
    part of the path. A malicious server could abuse this
    fact and effectively prevent libcurl-based clients to
    work with it - the PWD command is always issued on new
    FTP connections and the mistake has a high chance of
    causing a segfault. The simple fact that this has issue
    remained undiscovered for this long could suggest that
    malformed PWD responses are rare in benign servers. We
    are not aware of any exploit of this flaw. This bug was
    introduced in commit
    [415d2e7cb7](https://github.com/curl/curl/commit/415d2e
    7cb7), March 2005. In libcurl version 7.56.0, the
    parser always zero terminates the string but also
    rejects it if not terminated properly with a final
    double quote.(CVE-2017-1000254)

Note that Tenable Network Security has extracted the preceding
description block directly from the EulerOS security advisory. Tenable
has attempted to automatically clean and format it as much as possible
without introducing additional issues.");
  # https://developer.huawei.com/ict/en/site-euleros/euleros/security-advisories/EulerOS-SA-2017-1287
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?7de85d44");
  script_set_attribute(attribute:"solution", value:
"Update the affected curl package.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:N/I:N/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:N/I:N/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");

  script_set_attribute(attribute:"patch_publication_date", value:"2017/11/07");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:huawei:euleros:curl");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:huawei:euleros:libcurl");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:huawei:euleros:libcurl-devel");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:huawei:euleros:2.0");
  script_set_attribute(attribute:"plugin_publication_date", value:"2017/12/01");
  script_end_attributes();

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

  script_copyright(english:"This script is Copyright (C) 2017-2018 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/EulerOS/release", "Host/EulerOS/rpm-list", "Host/EulerOS/sp");
  script_exclude_keys("Host/EulerOS/uvp_version");

  exit(0);
}

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

if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);

release = get_kb_item("Host/EulerOS/release");
if (isnull(release) || release !~ "^EulerOS") audit(AUDIT_OS_NOT, "EulerOS");
if (release !~ "^EulerOS release 2\.0(\D|$)") audit(AUDIT_OS_NOT, "EulerOS 2.0");

sp = get_kb_item("Host/EulerOS/sp");
if (isnull(sp) || sp !~ "^(1)$") audit(AUDIT_OS_NOT, "EulerOS 2.0 SP1");

uvp = get_kb_item("Host/EulerOS/uvp_version");
if (!empty_or_null(uvp)) audit(AUDIT_OS_NOT, "EulerOS 2.0 SP1", "EulerOS UVP " + uvp);

if (!get_kb_item("Host/EulerOS/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);

cpu = get_kb_item("Host/cpu");
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ("x86_64" >!< cpu && cpu !~ "^i[3-6]86$") audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "EulerOS", cpu);

flag = 0;

pkgs = ["curl-7.29.0-35.h13",
        "libcurl-7.29.0-35.h13",
        "libcurl-devel-7.29.0-35.h13"];

foreach (pkg in pkgs)
  if (rpm_check(release:"EulerOS-2.0", sp:"1", reference:pkg)) flag++;

if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_WARNING,
    extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, "curl");
}