Vulnerabilities > CVE-2008-0216 - Permissions, Privileges, and Access Controls vulnerability in Freebsd

047910
CVSS 2.1 - LOW
Attack vector
LOCAL
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
NONE
Integrity impact
PARTIAL
Availability impact
NONE
local
low complexity
freebsd
CWE-264

Summary

The ptsname function in FreeBSD 6.0 through 7.0-PRERELEASE does not properly verify that a certain portion of a device name is associated with a pty of a user who is calling the pt_chown function, which might allow local users to read data from the pty from another user.

Common Attack Pattern Enumeration and Classification (CAPEC)

  • 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://www.gnucitizen.org/blog/danger-danger-danger/) 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.
  • Blue Boxing
    This type of attack against older telephone switches and trunks has been around for decades. A tone is sent by an adversary to impersonate a supervisor signal which has the effect of rerouting or usurping command of the line. While the US infrastructure proper may not contain widespread vulnerabilities to this type of attack, many companies are connected globally through call centers and business process outsourcing. These international systems may be operated in countries which have not upgraded Telco infrastructure and so are vulnerable to Blue boxing. Blue boxing is a result of failure on the part of the system to enforce strong authorization for administrative functions. While the infrastructure is different than standard current applications like web applications, there are historical lessons to be learned to upgrade the access control for administrative functions.
  • Restful Privilege Elevation
    Rest uses standard HTTP (Get, Put, Delete) style permissions methods, but these are not necessarily correlated generally with back end programs. Strict interpretation of HTTP get methods means that these HTTP Get services should not be used to delete information on the server, but there is no access control mechanism to back up this logic. This means that unless the services are properly ACL'd and the application's service implementation are following these guidelines then an HTTP request can easily execute a delete or update on the server side. The attacker identifies a HTTP Get URL such as http://victimsite/updateOrder, which calls out to a program to update orders on a database or other resource. The URL is not idempotent so the request can be submitted multiple times by the attacker, additionally, the attacker may be able to exploit the URL published as a Get method that actually performs updates (instead of merely retrieving data). This may result in malicious or inadvertent altering of data on the server.
  • Target Programs with Elevated Privileges
    This attack targets programs running with elevated privileges. The attacker would try to leverage a bug in the running program and get arbitrary code to execute with elevated privileges. For instance an attacker would look for programs that write to the system directories or registry keys (such as HKLM, which stores a number of critical Windows environment variables). These programs are typically running with elevated privileges and have usually not been designed with security in mind. Such programs are excellent exploit targets because they yield lots of power when they break. The malicious user try to execute its code at the same level as a privileged system call.

Seebug

bulletinFamilyexploit
descriptionBUGTRAQ ID: 27284 CVE(CAN) ID: CVE-2008-0216,CVE-2008-0217 FreeBSD就是一种运行在Intel平台上、可以自由使用的开放源码Unix类系统。 FreeBSD在处理pty的权限时存在漏洞,本地攻击者可能利用此漏洞提升自己的权限。 FreeBSD的openpty()函数在为打开的伪终端设置权限时存在错误,恶意的本地用户可以通过执行内部调用了openpty()的程序从非root用户所打开的pty读取文本;此外ptsname(3)函数错误的从/dev中的设备节点名获得了两个字符,但没有核实是否在操作调用用户所拥有的有效pty。pt_chown使用了ptsname(3)的错误结果将pty的所有权更改到调用pt_chown的用户,这样本地用户就可以获得正常情况下应受限的所有权。 FreeBSD FreeBSD 7.0 FreeBSD FreeBSD 6.3 FreeBSD FreeBSD 6.2 FreeBSD FreeBSD 6.1 FreeBSD FreeBSD 5.5 FreeBSD FreeBSD 5.0 厂商补丁: FreeBSD ------- FreeBSD已经为此发布了一个安全公告(FreeBSD-SA-08:01)以及相应补丁: FreeBSD-SA-08:01:pty snooping 链接:<a href=ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-08:01.pty.asc target=_blank>ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-08:01.pty.asc</a> 补丁下载: 执行以下步骤之一: 1) 将有漏洞的系统升级到5-STABLE、6-STABLE或7.0-PRERELEASE,或修改日期之后的RELENG_7_0、RELENG_6_3、RELENG_6_2、RELENG_6_1或RELENG_5_5安全版本。 2) 为当前系统打补丁: 以下补丁确认可应用于FreeBSD 5.5、6.1、6.2、6.3和7.0系统。 a) 从以下位置下载相关补丁,并使用PGP工具验证附带的PGP签名。 [FreeBSD 5.5] # fetch <a href=http://security.FreeBSD.org/patches/SA-08:01/pty5.patch target=_blank>http://security.FreeBSD.org/patches/SA-08:01/pty5.patch</a> # fetch <a href=http://security.FreeBSD.org/patches/SA-08:01/pty5.patch.asc target=_blank>http://security.FreeBSD.org/patches/SA-08:01/pty5.patch.asc</a> [FreeBSD 6.x] # fetch <a href=http://security.FreeBSD.org/patches/SA-08:01/pty6.patch target=_blank>http://security.FreeBSD.org/patches/SA-08:01/pty6.patch</a> # fetch <a href=http://security.FreeBSD.org/patches/SA-08:01/pty6.patch.asc target=_blank>http://security.FreeBSD.org/patches/SA-08:01/pty6.patch.asc</a> [FreeBSD 7.0] # fetch <a href=http://security.FreeBSD.org/patches/SA-08:01/pty7.patch target=_blank>http://security.FreeBSD.org/patches/SA-08:01/pty7.patch</a> # fetch <a href=http://security.FreeBSD.org/patches/SA-08:01/pty7.patch.asc target=_blank>http://security.FreeBSD.org/patches/SA-08:01/pty7.patch.asc</a> b) 以root执行以下命令: # cd /usr/src # patch &lt; /path/to/patch c) 如&lt;URL: <a href=http://www.freebsd.org/handbook/makeworld.html&gt; target=_blank>http://www.freebsd.org/handbook/makeworld.html&gt;</a> 所述重新编译操作系统并重启系统。
idSSV:2852
last seen2017-11-19
modified2008-01-23
published2008-01-23
reporterRoot
titleFreeBSD pty处理多个本地信息泄露漏洞