Simon McVittie 氏は、CVE-2014-3636 の修正が不適切であり、下層のサービス拒否ベクトルに完全に対処していないことを発見しました。この更新は、最初に D-Bus デーモンを root として開始するため、そのファイル記述子のカウントを適切に増やすことができます。

また、この更新では、以前のセキュリティ更新の auth_timeout の変更を古い値に戻します。新しい値は、一部のシステムで起動の失敗を引き起こすためです。悪意あるローカルユーザーに対して D-Bus デーモンを強化する方法の詳細については、README.Debian ファイルを参照してください。

1.6.28 的更新

請注意，Tenable Network Security 已直接從 Fedora 安全性公告擷取前置描述區塊。Tenable 已盡量在不造成其他問題的前提下，嘗試自動清理並將其格式化。

更新版 dbus 套件可修正下列安全性問題：

Alban Crequy 與 Simon McVittie 在 D-Bus 訊息程序中發現數個弱點：

在 64 位元平台中，檔案描述符號剖析可能會遭到本機使用者濫用，造成 dbus-daemon 發生堆積損毀，從而引發當機，或可能執行任意程式碼 (CVE-2014-3635)。

dbus-daemon 中存有一個拒絕服務弱點，會讓本機攻擊者藉由耗盡描述符號限制，禁止新的 dbus-daemon 連線，或是中斷現有用戶端連線 (CVE-2014-3636)。

惡意的本機使用者可建立 D-Bus 和 dbus-daemon 連線，而這無法透過鎖死參與的處理程序進行終止，從而導致拒絕服務弱點 (CVE-2014-3637)。

在用於追蹤哪些訊息會預期收到回覆的程式碼中，dbus-daemon 受到了拒絕服務弱點的影響，這可能會讓本機攻擊者降低 dbus-daemon 的效能 (CVE-2014-3638)。

dbus-daemon 未正確拒絕來自本機使用者的惡意連線，導致拒絕服務弱點 (CVE-2014-3639)。

D-Bus 維護者針對 CVE-2014-3636 發出的修補程式是根據不正確的推理，並且無法完全避免 CVE-2014-3636 第 A 部分中所載的攻擊 (如下文重述)。若要避免該攻擊，則必須將系統 dbus-daemon 的 RLIMIT_NOFILE (ulimit -n) 解析到更高的值。

惡意寄件者可藉由將允許的 fds 上限數排入佇列，進而達到系統 dbus-daemon 的 RLIMIT_NOFILE 限制 (即 ulimit -n，一般在 Linux 中是設為 1024)。而這可從兩個方面引發拒絕服務：

- 新用戶端將無法連線至 dbus-daemon

- 當收到含有 fd 的非惡意用戶端的後續訊息時，dbus-daemon 會收到 MSG_CTRUNC 旗標，表示 fd 清單被截斷；核心 fd-passing API 不提供任何復原此情形的方式，因此 dbus-daemon 回應 MSG_CTRUNC 的方式是將寄件者中斷連線，導致該寄件者被拒絕服務。

此更新也可解決 CVE-2014-7824 安全性弱點。

Dbus-1 已更新至 1.6.26 版，可修正一個安全性問題及其他數個問題。

已修正此安全性問題：

- 將 dbus-daemon 的 RLIMIT_NOFILE rlimit 提高到 65536，可阻止攻擊者耗盡系統匯流排的檔案描述符號 (CVE-2014-7824)。

據發現，DBus 未正確處理大量檔案描述符號訊息。本機攻擊者可利用此問題造成 DBus 停止回應，進而導致拒絕服務。
(CVE-2014-7824).

請注意，Tenable Network Security 已直接從 Ubuntu 安全性公告擷取前置描述區塊。Tenable 已盡量在不造成其他問題的前提下，嘗試自動清理並將其格式化。

Simon McVittie 發現，CVE-2014-3636 的修正有誤，因為其無法完全解決基礎拒絕服務向量。此更新最初會以 root 身分啟動 D-Bus 程序，以便正確提高檔案描述符號計數。

此外，此更新會將前版安全性更新中的 auth_timeout 變更還原為舊的值，因為新的值會造成部分系統開機失敗。請參閱 README.Debian 檔案，詳細瞭解如何加強 D-Bus 程序對惡意本機使用者的防範能力。

Update to 1.6.28

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

Simon McVittie reports :

The patch issued by the D-Bus maintainers for CVE-2014-3636 was based on incorrect reasoning, and does not fully prevent the attack described as 'CVE-2014-3636 part A', which is repeated below.
Preventing that attack requires raising the system dbus-daemon's RLIMIT_NOFILE (ulimit -n) to a higher value. CVE-2014-7824 has been allocated for this vulnerability.

The remote NewStart CGSL host, running version MAIN 6.02, has dbus packages installed that are affected by multiple vulnerabilities:

  - Unspecified vulnerability in the match_rule_equal function in bus/signals.c in D-Bus before 1.0.2 allows     local applications to remove match rules for other applications and cause a denial of service (lost     process messages). (CVE-2006-6107)

  - dbus-daemon in D-Bus before 1.0.3, and 1.1.x before 1.1.20, recognizes send_interface attributes in allow     directives in the security policy only for fully qualified method calls, which allows local users to     bypass intended access restrictions via a method call with a NULL interface. (CVE-2008-0595)

  - The _dbus_validate_signature_with_reason function (dbus-marshal-validate.c) in D-Bus (aka DBus) before     1.2.14 uses incorrect logic to validate a basic type, which allows remote attackers to spoof a signature     via a crafted key. NOTE: this is due to an incorrect fix for CVE-2008-3834. (CVE-2009-1189)

  - libdbus 1.5.x and earlier, when used in setuid or other privileged programs in X.org and possibly other     products, allows local users to gain privileges and execute arbitrary code via the DBUS_SYSTEM_BUS_ADDRESS     environment variable. NOTE: libdbus maintainers state that this is a vulnerability in the applications     that do not cleanse environment variables, not in libdbus itself: we do not support use of libdbus in     setuid binaries that do not sanitize their environment before their first call into libdbus.
    (CVE-2012-3524)

  - The _dbus_printf_string_upper_bound function in dbus/dbus-sysdeps-unix.c in D-Bus (aka DBus) 1.4.x before     1.4.26, 1.6.x before 1.6.12, and 1.7.x before 1.7.4 allows local users to cause a denial of service     (service crash) via a crafted message. (CVE-2013-2168)

  - The dbus-daemon in D-Bus 1.2.x through 1.4.x, 1.6.x before 1.6.20, and 1.8.x before 1.8.4, sends an     AccessDenied error to the service instead of a client when the client is prohibited from accessing the     service, which allows local users to cause a denial of service (initialization failure and exit) or     possibly conduct a side-channel attack via a D-Bus message to an inactive service. (CVE-2014-3477)

  - dbus 1.3.0 before 1.6.22 and 1.8.x before 1.8.6 allows local users to cause a denial of service     (disconnect) via a certain sequence of crafted messages that cause the dbus-daemon to forward a message     containing an invalid file descriptor. (CVE-2014-3533)

  - Off-by-one error in D-Bus 1.3.0 through 1.6.x before 1.6.24 and 1.8.x before 1.8.8, when running on a     64-bit system and the max_message_unix_fds limit is set to an odd number, allows local users to cause a     denial of service (dbus-daemon crash) or possibly execute arbitrary code by sending one more file     descriptor than the limit, which triggers a heap-based buffer overflow or an assertion failure.
    (CVE-2014-3635)

  - D-Bus 1.3.0 through 1.6.x before 1.6.24 and 1.8.x before 1.8.8 allows local users to (1) cause a denial of     service (prevention of new connections and connection drop) by queuing the maximum number of file     descriptors or (2) cause a denial of service (disconnect) via multiple messages that combine to have more     than the allowed number of file descriptors for a single sendmsg call. (CVE-2014-3636)

  - D-Bus 1.3.0 through 1.6.x before 1.6.24 and 1.8.x before 1.8.8 does not properly close connections for     processes that have terminated, which allows local users to cause a denial of service via a D-bus message     containing a D-Bus connection file descriptor. (CVE-2014-3637)

  - The bus_connections_check_reply function in config-parser.c in D-Bus before 1.6.24 and 1.8.x before 1.8.8     allows local users to cause a denial of service (CPU consumption) via a large number of method calls.
    (CVE-2014-3638)

  - The dbus-daemon in D-Bus before 1.6.24 and 1.8.x before 1.8.8 does not properly close old connections,     which allows local users to cause a denial of service (incomplete connection consumption and prevention of     new connections) via a large number of incomplete connections. (CVE-2014-3639)

  - D-Bus 1.3.0 through 1.6.x before 1.6.26, 1.8.x before 1.8.10, and 1.9.x before 1.9.2 allows local users to     cause a denial of service (prevention of new connections and connection drop) by queuing the maximum     number of file descriptors. NOTE: this vulnerability exists because of an incomplete fix for     CVE-2014-3636.1. (CVE-2014-7824)

  - D-Bus 1.4.x through 1.6.x before 1.6.30, 1.8.x before 1.8.16, and 1.9.x before 1.9.10 does not validate     the source of ActivationFailure signals, which allows local users to cause a denial of service (activation     failure error returned) by leveraging a race condition involving sending an ActivationFailure signal     before systemd responds. (CVE-2015-0245)

  - An issue was discovered in dbus >= 1.3.0 before 1.12.18. The DBusServer in libdbus, as used in dbus-     daemon, leaks file descriptors when a message exceeds the per-message file descriptor limit. A local     attacker with access to the D-Bus system bus or another system service's private AF_UNIX socket could use     this to make the system service reach its file descriptor limit, denying service to subsequent D-Bus     clients. (CVE-2020-12049)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote NewStart CGSL host, running version MAIN 6.06, has dbus packages installed that are affected by multiple vulnerabilities:

  - dbus before 1.10.28, 1.12.x before 1.12.16, and 1.13.x before 1.13.12, as used in DBusServer in Canonical     Upstart in Ubuntu 14.04 (and in some, less common, uses of dbus-daemon), allows cookie spoofing because of     symlink mishandling in the reference implementation of DBUS_COOKIE_SHA1 in the libdbus library. (This only     affects the DBUS_COOKIE_SHA1 authentication mechanism.) A malicious client with write access to its own     home directory could manipulate a ~/.dbus-keyrings symlink to cause a DBusServer with a different uid to     read and write in unintended locations. In the worst case, this could result in the DBusServer reusing a     cookie that is known to the malicious client, and treating that cookie as evidence that a subsequent     client connection came from an attacker-chosen uid, allowing authentication bypass. (CVE-2019-12749)

  - libdbus 1.5.x and earlier, when used in setuid or other privileged programs in X.org and possibly other     products, allows local users to gain privileges and execute arbitrary code via the DBUS_SYSTEM_BUS_ADDRESS     environment variable. NOTE: libdbus maintainers state that this is a vulnerability in the applications     that do not cleanse environment variables, not in libdbus itself: we do not support use of libdbus in     setuid binaries that do not sanitize their environment before their first call into libdbus.
    (CVE-2012-3524)

  - Unspecified vulnerability in the match_rule_equal function in bus/signals.c in D-Bus before 1.0.2 allows     local applications to remove match rules for other applications and cause a denial of service (lost     process messages). (CVE-2006-6107)

  - dbus-daemon in D-Bus before 1.0.3, and 1.1.x before 1.1.20, recognizes send_interface attributes in allow     directives in the security policy only for fully qualified method calls, which allows local users to     bypass intended access restrictions via a method call with a NULL interface. (CVE-2008-0595)

  - The _dbus_validate_signature_with_reason function (dbus-marshal-validate.c) in D-Bus (aka DBus) before     1.2.14 uses incorrect logic to validate a basic type, which allows remote attackers to spoof a signature     via a crafted key. NOTE: this is due to an incorrect fix for CVE-2008-3834. (CVE-2009-1189)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

ID	名稱	產品	系列	已發布	已更新	嚴重性
79886	Debian DSA-3099-1：dbus - セキュリティ更新	Nessus	Debian Local Security Checks	2014/12/15	2021/1/11	low
79924	Fedora 20 : dbus-1.6.28-1.fc20 (2014-16243)	Nessus	Fedora Local Security Checks	2014/12/15	2021/1/11	medium
79322	Mandriva Linux 安全性公告：dbus (MDVSA-2014:214)	Nessus	Mandriva Local Security Checks	2014/11/19	2021/1/6	medium
79350	openSUSE 安全性更新：dbus-1 (openSUSE-SU-2014:1454-1)	Nessus	SuSE Local Security Checks	2014/11/20	2021/1/19	low
79621	Ubuntu 14.04 LTS：DBus 弱點 (USN-2425-1)	Nessus	Ubuntu Local Security Checks	2014/11/28	2024/8/28	medium
79886	Debian DSA-3099-1：dbus - 安全性更新	Nessus	Debian Local Security Checks	2014/12/15	2021/1/11	low
80130	Fedora 19 : dbus-1.6.28-1.fc19 (2014-16227)	Nessus	Fedora Local Security Checks	2014/12/22	2021/1/11	medium
79197	FreeBSD : dbus -- incomplete fix for CVE-2014-3636 part A (c1930f45-6982-11e4-80e1-bcaec565249c)	Nessus	FreeBSD Local Security Checks	2014/11/12	2021/1/6	low
167488	NewStart CGSL MAIN 6.02 : dbus Multiple Vulnerabilities (NS-SA-2022-0093)	Nessus	NewStart CGSL Local Security Checks	2022/11/15	2022/11/16	medium
266270	NewStart CGSL MAIN 6.06 : dbus Multiple Vulnerabilities (NS-SA-2025-0231)	Nessus	NewStart CGSL Local Security Checks	2025/9/30	2025/9/30	high

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