Vulnerabilities > CVE-2011-4415 - Improper Input Validation vulnerability in Apache Http Server

047910
CVSS 1.2 - LOW
Attack vector
LOCAL
Attack complexity
HIGH
Privileges required
NONE
Confidentiality impact
NONE
Integrity impact
NONE
Availability impact
PARTIAL
local
high complexity
apache
CWE-20
nessus
exploit available

Summary

The ap_pregsub function in server/util.c in the Apache HTTP Server 2.0.x through 2.0.64 and 2.2.x through 2.2.21, when the mod_setenvif module is enabled, does not restrict the size of values of environment variables, which allows local users to cause a denial of service (memory consumption or NULL pointer dereference) via a .htaccess file with a crafted SetEnvIf directive, in conjunction with a crafted HTTP request header, related to (1) the "len +=" statement and (2) the apr_pcalloc function call, a different vulnerability than CVE-2011-3607.

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Buffer Overflow via Environment Variables
    This attack pattern involves causing a buffer overflow through manipulation of environment variables. Once the attacker finds that they can modify an environment variable, they may try to overflow associated buffers. This attack leverages implicit trust often placed in environment variables.
  • Server Side Include (SSI) Injection
    An attacker can use Server Side Include (SSI) Injection to send code to a web application that then gets executed by the web server. Doing so enables the attacker to achieve similar results to Cross Site Scripting, viz., arbitrary code execution and information disclosure, albeit on a more limited scale, since the SSI directives are nowhere near as powerful as a full-fledged scripting language. Nonetheless, the attacker can conveniently gain access to sensitive files, such as password files, and execute shell commands.
  • Cross Zone Scripting
    An attacker is able to cause a victim to load content into their web-browser that bypasses security zone controls and gain access to increased privileges to execute scripting code or other web objects such as unsigned ActiveX controls or applets. This is a privilege elevation attack targeted at zone-based web-browser security. In a zone-based model, pages belong to one of a set of zones corresponding to the level of privilege assigned to that page. Pages in an untrusted zone would have a lesser level of access to the system and/or be restricted in the types of executable content it was allowed to invoke. In a cross-zone scripting attack, a page that should be assigned to a less privileged zone is granted the privileges of a more trusted zone. This can be accomplished by exploiting bugs in the browser, exploiting incorrect configuration in the zone controls, through a cross-site scripting attack that causes the attackers' content to be treated as coming from a more trusted page, or by leveraging some piece of system functionality that is accessible from both the trusted and less trusted zone. This attack differs from "Restful Privilege Escalation" in that the latter correlates to the inadequate securing of RESTful access methods (such as HTTP DELETE) on the server, while cross-zone scripting attacks the concept of security zones as implemented by a browser.
  • Cross Site Scripting through Log Files
    An attacker may leverage a system weakness where logs are susceptible to log injection to insert scripts into the system's logs. If these logs are later viewed by an administrator through a thin administrative interface and the log data is not properly HTML encoded before being written to the page, the attackers' scripts stored in the log will be executed in the administrative interface with potentially serious consequences. This attack pattern is really a combination of two other attack patterns: log injection and stored cross site scripting.
  • Command Line Execution through SQL Injection
    An attacker uses standard SQL injection methods to inject data into the command line for execution. This could be done directly through misuse of directives such as MSSQL_xp_cmdshell or indirectly through injection of data into the database that would be interpreted as shell commands. Sometime later, an unscrupulous backend application (or could be part of the functionality of the same application) fetches the injected data stored in the database and uses this data as command line arguments without performing proper validation. The malicious data escapes that data plane by spawning new commands to be executed on the host.

Exploit-Db

descriptionApache < 2.0.64 / < 2.2.21 mod_setenvif - Integer Overflow. CVE-2011-3607,CVE-2011-4415. Dos exploit for Linux platform
idEDB-ID:41769
last seen2017-03-29
modified2011-11-02
published2011-11-02
reporterExploit-DB
sourcehttps://www.exploit-db.com/download/41769/
titleApache < 2.0.64 / < 2.2.21 mod_setenvif - Integer Overflow

Nessus

NASL familyWeb Servers
NASL idHPSMH_7_1_1_1.NASL
descriptionAccording to the web server
last seen2020-06-01
modified2020-06-02
plugin id59851
published2012-07-05
reporterThis script is Copyright (C) 2012-2019 and is owned by Tenable, Inc. or an Affiliate thereof.
sourcehttps://www.tenable.com/plugins/nessus/59851
titleHP System Management Homepage < 7.1.1 Multiple Vulnerabilities

Seebug

bulletinFamilyexploit
descriptionBUGTRAQ ID: 50639 CVE ID: CVE-2011-4415 Apache HTTP Server是Apache软件基金会的一个开放源码的网页服务器,可以在大多数计算机操作系统中运行。 Apache HTTP Server 2.0.x至2.0.64及2.2.x至2.2.21内server/util.c中的ap_pregsub函数,在启用了mod_setenvif模块后,没有限制环境变量的值大小,通过带有特制SetEnvIf指令的.htaccess文件和HTTP请求标头,导致拒绝服务(内存破坏或空指针引用)。 0 Apache 2.2.x 厂商补丁: Apache Group ------------ 目前厂商还没有提供补丁或者升级程序,我们建议使用此软件的用户随时关注厂商的主页以获取最新版本: http://www.apache.org
idSSV:60250
last seen2017-11-19
modified2012-07-02
published2012-07-02
reporterRoot
titleApache HTTP Server 'ap_pregsub()'函数本地拒绝服务漏洞(CVE-2011-4415)