ID CVE-2017-8806
Summary The Debian pg_ctlcluster, pg_createcluster, and pg_upgradecluster scripts, as distributed in the Debian postgresql-common package before 181+deb9u1 for PostgreSQL (and other packages related to Debian and Ubuntu), handled symbolic links insecurely, which could result in local denial of service by overwriting arbitrary files.
Vulnerable Configurations
  • PostgreSQL for Debian
  • PostgreSQL for Ubuntu
  • Canonical Ubuntu Linux 14.04 LTS (Long-Term Support)
  • Canonical Ubuntu Linux 16.04 LTS (Long-Term Support)
  • Canonical Ubuntu Linux 17.04
  • Canonical Ubuntu Linux 17.10
  • Debian Linux 8.0 (Jessie)
  • Debian Linux 9.0
Base: 3.6
  • Symlink Attack
    An attacker positions a symbolic link in such a manner that the targeted user or application accesses the link's endpoint, assuming that it is accessing a file with the link's name. The endpoint file may be either output or input. If the file is output, the result is that the endpoint is modified, instead of a file at the intended location. Modifications to the endpoint file may include appending, overwriting, corrupting, changing permissions, or other modifications. In some variants of this attack the attacker may be able to control the change to a file while in other cases they cannot. The former is especially damaging since the attacker may be able to grant themselves increased privileges or insert false information, but the latter can also be damaging as it can expose sensitive information or corrupt or destroy vital system or application files. Alternatively, the endpoint file may serve as input to the targeted application. This can be used to feed malformed input into the target or to cause the target to process different information, possibly allowing the attacker to control the actions of the target or to cause the target to expose information to the attacker. Moreover, the actions taken on the endpoint file are undertaken with the permissions of the targeted user or application, which may exceed the permissions that the attacker would normally have.
  • Accessing, Modifying or Executing Executable Files
    An attack of this type exploits a system's configuration that allows an attacker to either directly access an executable file, for example through shell access; or in a possible worst case allows an attacker to upload a file and then execute it. Web servers, ftp servers, and message oriented middleware systems which have many integration points are particularly vulnerable, because both the programmers and the administrators must be in synch regarding the interfaces and the correct privileges for each interface.
  • Leverage Executable Code in Non-Executable Files
    An attack of this type exploits a system's trust in configuration and resource files, when the executable loads the resource (such as an image file or configuration file) the attacker has modified the file to either execute malicious code directly or manipulate the target process (e.g. application server) to execute based on the malicious configuration parameters. Since systems are increasingly interrelated mashing up resources from local and remote sources the possibility of this attack occurring is high. The attack can be directed at a client system, such as causing buffer overrun through loading seemingly benign image files, as in Microsoft Security Bulletin MS04-028 where specially crafted JPEG files could cause a buffer overrun once loaded into the browser. Another example targets clients reading pdf files. In this case the attacker simply appends javascript to the end of a legitimate url for a pdf ( http://path/to/pdf/file.pdf#whatever_name_you_want=javascript:your_code_here The client assumes that they are reading a pdf, but the attacker has modified the resource and loaded executable javascript into the client's browser process. The attack can also target server processes. The attacker edits the resource or configuration file, for example a web.xml file used to configure security permissions for a J2EE app server, adding role name "public" grants all users with the public role the ability to use the administration functionality. The server trusts its configuration file to be correct, but when they are manipulated, the attacker gains full control.
  • Manipulating Input to File System Calls
    An attacker manipulates inputs to the target software which the target software passes to file system calls in the OS. The goal is to gain access to, and perhaps modify, areas of the file system that the target software did not intend to be accessible.
nessus via4
  • NASL family Debian Local Security Checks
    description It was discovered that the pg_ctlcluster, pg_createcluster and pg_upgradecluster commands handled symbolic links insecurely which could result in local denial of service by overwriting arbitrary files.
    last seen 2018-11-13
    modified 2018-11-10
    plugin id 104485
    published 2017-11-10
    reporter Tenable
    title Debian DSA-4029-1 : postgresql-common - security update
  • NASL family Ubuntu Local Security Checks
    NASL id UBUNTU_USN-3476-1.NASL
    description Dawid Golunski discovered that the postgresql-common pg_ctlcluster script incorrectly handled symlinks. A local attacker could possibly use this issue to escalate privileges. This issue only affected Ubuntu 14.04 LTS and Ubuntu 16.04 LTS. (CVE-2016-1255) It was discovered that the postgresql-common helper scripts incorrectly handled symlinks. A local attacker could possibly use this issue to escalate privileges. (CVE-2017-8806). Note that Tenable Network Security has extracted the preceding description block directly from the Ubuntu security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
    last seen 2018-12-02
    modified 2018-12-01
    plugin id 104496
    published 2017-11-10
    reporter Tenable
    title Ubuntu 14.04 LTS / 16.04 LTS / 17.04 / 17.10 : postgresql-common vulnerabilities (USN-3476-1)
refmap via4
bid 101810
Last major update 13-11-2017 - 04:29
Published 13-11-2017 - 04:29
Last modified 08-12-2017 - 13:42
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