Ubuntu 16.04 ESM / 18.04 ESM / 20.04 ESM : Redis vulnerabilities (USN-5221-1)

2023-10-1600:00:00

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The remote Ubuntu 16.04 ESM / 18.04 ESM / 20.04 ESM host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-5221-1 advisory.

Redis is an open source, in-memory database that persists on disk. In affected versions specially crafted Lua scripts executing in Redis can cause the heap-based Lua stack to be overflowed, due to incomplete checks for this condition. This can result with heap corruption and potentially remote code execution.
This problem exists in all versions of Redis with Lua scripting support, starting from 2.6. The problem is fixed in versions 6.2.6, 6.0.16 and 5.0.14. For users unable to update an additional workaround to mitigate the problem without patching the redis-server executable is to prevent users from executing Lua scripts. This can be done using ACL to restrict EVAL and EVALSHA commands. (CVE-2021-32626)
Redis is an open source, in-memory database that persists on disk. In affected versions an integer overflow bug in Redis can be exploited to corrupt the heap and potentially result with remote code execution. The vulnerability involves changing the default proto-max-bulk-len and client-query-buffer- limit configuration parameters to very large values and constructing specially crafted very large stream elements. The problem is fixed in Redis 6.2.6, 6.0.16 and 5.0.14. For users unable to upgrade an additional workaround to mitigate the problem without patching the redis-server executable is to prevent users from modifying the proto-max-bulk-len configuration parameter. This can be done using ACL to restrict unprivileged users from using the CONFIG SET command. (CVE-2021-32627)
Redis is an open source, in-memory database that persists on disk. An integer overflow bug in the ziplist data structure used by all versions of Redis can be exploited to corrupt the heap and potentially result with remote code execution. The vulnerability involves modifying the default ziplist configuration parameters (hash-max-ziplist-entries, hash-max-ziplist-value, zset-max-ziplist-entries or zset-max- ziplist-value) to a very large value, and then constructing specially crafted commands to create very large ziplists. The problem is fixed in Redis versions 6.2.6, 6.0.16, 5.0.14. An additional workaround to mitigate the problem without patching the redis-server executable is to prevent users from modifying the above configuration parameters. This can be done using ACL to restrict unprivileged users from using the CONFIG SET command. (CVE-2021-32628)
Redis is an open source, in-memory database that persists on disk. When using the Redis Lua Debugger, users can send malformed requests that cause the debugger’s protocol parser to read data beyond the actual buffer. This issue affects all versions of Redis with Lua debugging support (3.2 or newer). The problem is fixed in versions 6.2.6, 6.0.16 and 5.0.14. (CVE-2021-32672)
Redis is an open source, in-memory database that persists on disk. When parsing an incoming Redis Standard Protocol (RESP) request, Redis allocates memory according to user-specified values which determine the number of elements (in the multi-bulk header) and size of each element (in the bulk header). An attacker delivering specially crafted requests over multiple connections can cause the server to allocate significant amount of memory. Because the same parsing mechanism is used to handle authentication requests, this vulnerability can also be exploited by unauthenticated users. The problem is fixed in Redis versions 6.2.6, 6.0.16 and 5.0.14. An additional workaround to mitigate this problem without patching the redis-server executable is to block access to prevent unauthenticated users from connecting to Redis. This can be done in different ways: Using network access control tools like firewalls, iptables, security groups, etc. or Enabling TLS and requiring users to authenticate using client side certificates.
(CVE-2021-32675)
Redis is an open source, in-memory database that persists on disk. An integer overflow bug affecting all versions of Redis can be exploited to corrupt the heap and potentially be used to leak arbitrary contents of the heap or trigger remote code execution. The vulnerability involves changing the default set-max- intset-entries configuration parameter to a very large value and constructing specially crafted commands to manipulate sets. The problem is fixed in Redis versions 6.2.6, 6.0.16 and 5.0.14. An additional workaround to mitigate the problem without patching the redis-server executable is to prevent users from modifying the set-max-intset-entries configuration parameter. This can be done using ACL to restrict unprivileged users from using the CONFIG SET command. (CVE-2021-32687)
Redis is an open source, in-memory database that persists on disk. An integer overflow bug in the underlying string library can be used to corrupt the heap and potentially result with denial of service or remote code execution. The vulnerability involves changing the default proto-max-bulk-len configuration parameter to a very large value and constructing specially crafted network payloads or commands. The problem is fixed in Redis versions 6.2.6, 6.0.16 and 5.0.14. An additional workaround to mitigate the problem without patching the redis-server executable is to prevent users from modifying the proto-max- bulk-len configuration parameter. This can be done using ACL to restrict unprivileged users from using the CONFIG SET command. (CVE-2021-41099)
Redis is an in-memory database that persists on disk. A vulnerability involving out-of-bounds read and integer overflow to buffer overflow exists starting with version 2.2 and prior to versions 5.0.13, 6.0.15, and 6.2.5. On 32-bit systems, Redis *BIT* command are vulnerable to integer overflow that can potentially be exploited to corrupt the heap, leak arbitrary heap contents or trigger remote code execution. The vulnerability involves changing the default proto-max-bulk-len configuration parameter to a very large value and constructing specially crafted commands bit commands. This problem only affects Redis on 32-bit platforms, or compiled as a 32-bit binary. Redis versions 5.0.3m 6.0.15, and 6.2.5 contain patches for this issue. An additional workaround to mitigate the problem without patching the redis-serverexecutable is to prevent users from modifying theproto-max-bulk-len` configuration parameter. This can be done using ACL to restrict unprivileged users from using the CONFIG SET command.
(CVE-2021-32761)
Redis is an open-source, in-memory database that persists on disk. In affected versions of Redis an integer overflow bug in 32-bit Redis version 4.0 or newer could be exploited to corrupt the heap and potentially result with remote code execution. Redis 4.0 or newer uses a configurable limit for the maximum supported bulk input size. By default, it is 512MB which is a safe value for all platforms. If the limit is significantly increased, receiving a large request from a client may trigger several integer overflow scenarios, which would result with buffer overflow and heap corruption. We believe this could in certain conditions be exploited for remote code execution. By default, authenticated Redis users have access to all configuration parameters and can therefore use the CONFIG SET proto-max-bulk-len to change the safe default, making the system vulnerable. This problem only affects 32-bit Redis (on a 32-bit system, or as a 32-bit executable running on a 64-bit system). The problem is fixed in version 6.2, and the fix is back ported to 6.0.11 and 5.0.11. Make sure you use one of these versions if you are running 32-bit Redis. An additional workaround to mitigate the problem without patching the redis-server executable is to prevent clients from directly executing CONFIG SET: Using Redis 6.0 or newer, ACL configuration can be used to block the command. Using older versions, the rename-command configuration directive can be used to rename the command to a random string unknown to users, rendering it inaccessible. Please note that this workaround may have an additional impact on users or operational systems that expect CONFIG SET to behave in certain ways. (CVE-2021-21309)

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 Ubuntu Security Notice USN-5221-1. The text
# itself is copyright (C) Canonical, Inc. See
# <https://ubuntu.com/security/notices>. Ubuntu(R) is a registered
# trademark of Canonical, Inc.
##

include('compat.inc');

if (description)
{
  script_id(183135);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2023/12/22");

  script_cve_id(
    "CVE-2021-21309",
    "CVE-2021-32626",
    "CVE-2021-32627",
    "CVE-2021-32628",
    "CVE-2021-32672",
    "CVE-2021-32675",
    "CVE-2021-32687",
    "CVE-2021-32761",
    "CVE-2021-41099"
  );
  script_xref(name:"USN", value:"5221-1");

  script_name(english:"Ubuntu 16.04 ESM / 18.04 ESM / 20.04 ESM : Redis vulnerabilities (USN-5221-1)");

  script_set_attribute(attribute:"synopsis", value:
"The remote Ubuntu host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The remote Ubuntu 16.04 ESM / 18.04 ESM / 20.04 ESM host has packages installed that are affected by multiple
vulnerabilities as referenced in the USN-5221-1 advisory.

  - Redis is an open source, in-memory database that persists on disk. In affected versions specially crafted
    Lua scripts executing in Redis can cause the heap-based Lua stack to be overflowed, due to incomplete
    checks for this condition. This can result with heap corruption and potentially remote code execution.
    This problem exists in all versions of Redis with Lua scripting support, starting from 2.6. The problem is
    fixed in versions 6.2.6, 6.0.16 and 5.0.14. For users unable to update an additional workaround to
    mitigate the problem without patching the redis-server executable is to prevent users from executing Lua
    scripts. This can be done using ACL to restrict EVAL and EVALSHA commands. (CVE-2021-32626)

  - Redis is an open source, in-memory database that persists on disk. In affected versions an integer
    overflow bug in Redis can be exploited to corrupt the heap and potentially result with remote code
    execution. The vulnerability involves changing the default proto-max-bulk-len and client-query-buffer-
    limit configuration parameters to very large values and constructing specially crafted very large stream
    elements. The problem is fixed in Redis 6.2.6, 6.0.16 and 5.0.14. For users unable to upgrade an
    additional workaround to mitigate the problem without patching the redis-server executable is to prevent
    users from modifying the proto-max-bulk-len configuration parameter. This can be done using ACL to
    restrict unprivileged users from using the CONFIG SET command. (CVE-2021-32627)

  - Redis is an open source, in-memory database that persists on disk. An integer overflow bug in the ziplist
    data structure used by all versions of Redis can be exploited to corrupt the heap and potentially result
    with remote code execution. The vulnerability involves modifying the default ziplist configuration
    parameters (hash-max-ziplist-entries, hash-max-ziplist-value, zset-max-ziplist-entries or zset-max-
    ziplist-value) to a very large value, and then constructing specially crafted commands to create very
    large ziplists. The problem is fixed in Redis versions 6.2.6, 6.0.16, 5.0.14. An additional workaround to
    mitigate the problem without patching the redis-server executable is to prevent users from modifying the
    above configuration parameters. This can be done using ACL to restrict unprivileged users from using the
    CONFIG SET command. (CVE-2021-32628)

  - Redis is an open source, in-memory database that persists on disk. When using the Redis Lua Debugger,
    users can send malformed requests that cause the debugger's protocol parser to read data beyond the actual
    buffer. This issue affects all versions of Redis with Lua debugging support (3.2 or newer). The problem is
    fixed in versions 6.2.6, 6.0.16 and 5.0.14. (CVE-2021-32672)

  - Redis is an open source, in-memory database that persists on disk. When parsing an incoming Redis Standard
    Protocol (RESP) request, Redis allocates memory according to user-specified values which determine the
    number of elements (in the multi-bulk header) and size of each element (in the bulk header). An attacker
    delivering specially crafted requests over multiple connections can cause the server to allocate
    significant amount of memory. Because the same parsing mechanism is used to handle authentication
    requests, this vulnerability can also be exploited by unauthenticated users. The problem is fixed in Redis
    versions 6.2.6, 6.0.16 and 5.0.14. An additional workaround to mitigate this problem without patching the
    redis-server executable is to block access to prevent unauthenticated users from connecting to Redis. This
    can be done in different ways: Using network access control tools like firewalls, iptables, security
    groups, etc. or Enabling TLS and requiring users to authenticate using client side certificates.
    (CVE-2021-32675)

  - Redis is an open source, in-memory database that persists on disk. An integer overflow bug affecting all
    versions of Redis can be exploited to corrupt the heap and potentially be used to leak arbitrary contents
    of the heap or trigger remote code execution. The vulnerability involves changing the default set-max-
    intset-entries configuration parameter to a very large value and constructing specially crafted commands
    to manipulate sets. The problem is fixed in Redis versions 6.2.6, 6.0.16 and 5.0.14. An additional
    workaround to mitigate the problem without patching the redis-server executable is to prevent users from
    modifying the set-max-intset-entries configuration parameter. This can be done using ACL to restrict
    unprivileged users from using the CONFIG SET command. (CVE-2021-32687)

  - Redis is an open source, in-memory database that persists on disk. An integer overflow bug in the
    underlying string library can be used to corrupt the heap and potentially result with denial of service or
    remote code execution. The vulnerability involves changing the default proto-max-bulk-len configuration
    parameter to a very large value and constructing specially crafted network payloads or commands. The
    problem is fixed in Redis versions 6.2.6, 6.0.16 and 5.0.14. An additional workaround to mitigate the
    problem without patching the redis-server executable is to prevent users from modifying the proto-max-
    bulk-len configuration parameter. This can be done using ACL to restrict unprivileged users from using the
    CONFIG SET command. (CVE-2021-41099)

  - Redis is an in-memory database that persists on disk. A vulnerability involving out-of-bounds read and
    integer overflow to buffer overflow exists starting with version 2.2 and prior to versions 5.0.13, 6.0.15,
    and 6.2.5. On 32-bit systems, Redis `*BIT*` command are vulnerable to integer overflow that can
    potentially be exploited to corrupt the heap, leak arbitrary heap contents or trigger remote code
    execution. The vulnerability involves changing the default `proto-max-bulk-len` configuration parameter to
    a very large value and constructing specially crafted commands bit commands. This problem only affects
    Redis on 32-bit platforms, or compiled as a 32-bit binary. Redis versions 5.0.`3m 6.0.15, and 6.2.5
    contain patches for this issue. An additional workaround to mitigate the problem without patching the
    `redis-server` executable is to prevent users from modifying the `proto-max-bulk-len` configuration
    parameter. This can be done using ACL to restrict unprivileged users from using the CONFIG SET command.
    (CVE-2021-32761)

  - Redis is an open-source, in-memory database that persists on disk. In affected versions of Redis an
    integer overflow bug in 32-bit Redis version 4.0 or newer could be exploited to corrupt the heap and
    potentially result with remote code execution. Redis 4.0 or newer uses a configurable limit for the
    maximum supported bulk input size. By default, it is 512MB which is a safe value for all platforms. If the
    limit is significantly increased, receiving a large request from a client may trigger several integer
    overflow scenarios, which would result with buffer overflow and heap corruption. We believe this could in
    certain conditions be exploited for remote code execution. By default, authenticated Redis users have
    access to all configuration parameters and can therefore use the CONFIG SET proto-max-bulk-len to change
    the safe default, making the system vulnerable. **This problem only affects 32-bit Redis (on a 32-bit
    system, or as a 32-bit executable running on a 64-bit system).** The problem is fixed in version 6.2, and
    the fix is back ported to 6.0.11 and 5.0.11. Make sure you use one of these versions if you are running
    32-bit Redis. An additional workaround to mitigate the problem without patching the redis-server
    executable is to prevent clients from directly executing `CONFIG SET`: Using Redis 6.0 or newer, ACL
    configuration can be used to block the command. Using older versions, the `rename-command` configuration
    directive can be used to rename the command to a random string unknown to users, rendering it
    inaccessible. Please note that this workaround may have an additional impact on users or operational
    systems that expect `CONFIG SET` to behave in certain ways. (CVE-2021-21309)

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://ubuntu.com/security/notices/USN-5221-1");
  script_set_attribute(attribute:"solution", value:
"Update the affected packages.");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:S/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:L/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-2021-32626");

  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:"2021/02/26");
  script_set_attribute(attribute:"patch_publication_date", value:"2022/08/03");
  script_set_attribute(attribute:"plugin_publication_date", value:"2023/10/16");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:16.04:-:esm");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:18.04:-:esm");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:canonical:ubuntu_linux:20.04:-:esm");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:redis");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:redis-sentinel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:redis-server");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:canonical:ubuntu_linux:redis-tools");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

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

  script_copyright(english:"Ubuntu Security Notice (C) 2023 Canonical, Inc. / NASL script (C) 2023 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("ssh_get_info.nasl");
  script_require_keys("Host/cpu", "Host/Ubuntu", "Host/Ubuntu/release", "Host/Debian/dpkg-l");

  exit(0);
}

include('debian_package.inc');

if ( ! get_kb_item('Host/local_checks_enabled') ) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_release = get_kb_item('Host/Ubuntu/release');
if ( isnull(os_release) ) audit(AUDIT_OS_NOT, 'Ubuntu');
os_release = chomp(os_release);
if (! ('16.04' >< os_release || '18.04' >< os_release || '20.04' >< os_release)) audit(AUDIT_OS_NOT, 'Ubuntu 16.04 / 18.04 / 20.04', 'Ubuntu ' + os_release);
if ( ! get_kb_item('Host/Debian/dpkg-l') ) 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, 'Ubuntu', cpu);

var pkgs = [
    {'osver': '16.04', 'pkgname': 'redis-sentinel', 'pkgver': '2:3.0.6-1ubuntu0.4+esm1'},
    {'osver': '16.04', 'pkgname': 'redis-server', 'pkgver': '2:3.0.6-1ubuntu0.4+esm1'},
    {'osver': '16.04', 'pkgname': 'redis-tools', 'pkgver': '2:3.0.6-1ubuntu0.4+esm1'},
    {'osver': '18.04', 'pkgname': 'redis', 'pkgver': '5:4.0.9-1ubuntu0.2+esm3'},
    {'osver': '18.04', 'pkgname': 'redis-sentinel', 'pkgver': '5:4.0.9-1ubuntu0.2+esm3'},
    {'osver': '18.04', 'pkgname': 'redis-server', 'pkgver': '5:4.0.9-1ubuntu0.2+esm3'},
    {'osver': '18.04', 'pkgname': 'redis-tools', 'pkgver': '5:4.0.9-1ubuntu0.2+esm3'},
    {'osver': '20.04', 'pkgname': 'redis', 'pkgver': '5:5.0.7-2ubuntu0.1+esm1'},
    {'osver': '20.04', 'pkgname': 'redis-sentinel', 'pkgver': '5:5.0.7-2ubuntu0.1+esm1'},
    {'osver': '20.04', 'pkgname': 'redis-server', 'pkgver': '5:5.0.7-2ubuntu0.1+esm1'},
    {'osver': '20.04', 'pkgname': 'redis-tools', 'pkgver': '5:5.0.7-2ubuntu0.1+esm1'}
];

var flag = 0;
foreach package_array ( pkgs ) {
  var osver = NULL;
  var pkgname = NULL;
  var pkgver = NULL;
  if (!empty_or_null(package_array['osver'])) osver = package_array['osver'];
  if (!empty_or_null(package_array['pkgname'])) pkgname = package_array['pkgname'];
  if (!empty_or_null(package_array['pkgver'])) pkgver = package_array['pkgver'];
  if (osver && pkgname && pkgver) {
    if (ubuntu_check(osver:osver, pkgname:pkgname, pkgver:pkgver)) flag++;
  }
}

if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_WARNING,
    extra      : ubuntu_report_get()
  );
  exit(0);
}
else
{
  var tested = ubuntu_pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'redis / redis-sentinel / redis-server / redis-tools');
}

VendorProductVersionCPE
canonicalubuntu_linux16.04cpe:/o:canonical:ubuntu_linux:16.04:-:esm
canonicalubuntu_linux18.04cpe:/o:canonical:ubuntu_linux:18.04:-:esm
canonicalubuntu_linux20.04cpe:/o:canonical:ubuntu_linux:20.04:-:esm
canonicalubuntu_linuxredisp-cpe:/a:canonical:ubuntu_linux:redis
canonicalubuntu_linuxredis-sentinelp-cpe:/a:canonical:ubuntu_linux:redis-sentinel
canonicalubuntu_linuxredis-serverp-cpe:/a:canonical:ubuntu_linux:redis-server
canonicalubuntu_linuxredis-toolsp-cpe:/a:canonical:ubuntu_linux:redis-tools

Vendor	Product	Version	CPE
canonical	ubuntu_linux	16.04	cpe:/o:canonical:ubuntu_linux:16.04:-:esm
canonical	ubuntu_linux	18.04	cpe:/o:canonical:ubuntu_linux:18.04:-:esm
canonical	ubuntu_linux	20.04	cpe:/o:canonical:ubuntu_linux:20.04:-:esm
canonical	ubuntu_linux	redis	p-cpe:/a:canonical:ubuntu_linux:redis
canonical	ubuntu_linux	redis-sentinel	p-cpe:/a:canonical:ubuntu_linux:redis-sentinel
canonical	ubuntu_linux	redis-server	p-cpe:/a:canonical:ubuntu_linux:redis-server
canonical	ubuntu_linux	redis-tools	p-cpe:/a:canonical:ubuntu_linux:redis-tools