Vulnerabilities > CVE-2018-20250 - Path Traversal vulnerability in Rarlab Winrar
Attack vector
LOCAL Attack complexity
LOW Privileges required
NONE Confidentiality impact
HIGH Integrity impact
HIGH Availability impact
HIGH Summary
In WinRAR versions prior to and including 5.61, There is path traversal vulnerability when crafting the filename field of the ACE format (in UNACEV2.dll). When the filename field is manipulated with specific patterns, the destination (extraction) folder is ignored, thus treating the filename as an absolute path.
Vulnerable Configurations
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Relative Path Traversal An attacker exploits a weakness in input validation on the target by supplying a specially constructed path utilizing dot and slash characters for the purpose of obtaining access to arbitrary files or resources. An attacker modifies a known path on the target in order to reach material that is not available through intended channels. These attacks normally involve adding additional path separators (/ or \) and/or dots (.), or encodings thereof, in various combinations in order to reach parent directories or entirely separate trees of the target's directory structure.
- Directory Traversal An attacker with access to file system resources, either directly or via application logic, will use various file path specification or navigation mechanisms such as ".." in path strings and absolute paths to extend their range of access to inappropriate areas of the file system. The attacker attempts to either explore the file system for recon purposes or access directories and files that are intended to be restricted from their access. Exploring the file system can be achieved through constructing paths presented to directory listing programs, such as "ls" and 'dir', or through specially crafted programs that attempt to explore the file system. The attacker engaging in this type of activity is searching for information that can be used later in a more exploitive attack. Access to restricted directories or files can be achieved through modification of path references utilized by system applications.
- File System Function Injection, Content Based An attack of this type exploits the host's trust in executing remote content including binary files. The files are poisoned with a malicious payload (targeting the file systems accessible by the target software) by the attacker and may be passed through standard channels such as via email, and standard web content like PDF and multimedia files. The attacker exploits known vulnerabilities or handling routines in the target processes. Vulnerabilities of this type have been found in a wide variety of commercial applications from Microsoft Office to Adobe Acrobat and Apple Safari web browser. When the attacker knows the standard handling routines and can identify vulnerabilities and entry points they can be exploited by otherwise seemingly normal content. Once the attack is executed, the attackers' program can access relative directories such as C:\Program Files or other standard system directories to launch further attacks. In a worst case scenario, these programs are combined with other propagation logic and work as a virus.
- Using Slashes and URL Encoding Combined to Bypass Validation Logic This attack targets the encoding of the URL combined with the encoding of the slash characters. An attacker can take advantage of the multiple way of encoding an URL and abuse the interpretation of the URL. An URL may contain special character that need special syntax handling in order to be interpreted. Special characters are represented using a percentage character followed by two digits representing the octet code of the original character (%HEX-CODE). For instance US-ASCII space character would be represented with %20. This is often referred as escaped ending or percent-encoding. Since the server decodes the URL from the requests, it may restrict the access to some URL paths by validating and filtering out the URL requests it received. An attacker will try to craft an URL with a sequence of special characters which once interpreted by the server will be equivalent to a forbidden URL. It can be difficult to protect against this attack since the URL can contain other format of encoding such as UTF-8 encoding, Unicode-encoding, etc.
- 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.
Exploit-Db
file exploits/windows/local/46552.py id EDB-ID:46552 last seen 2019-03-17 modified 2019-02-22 platform windows port published 2019-02-22 reporter Exploit-DB source https://www.exploit-db.com/download/46552 title WinRAR 5.61 - Path Traversal type local file exploits/windows/local/46756.rb id EDB-ID:46756 last seen 2019-04-25 modified 2019-04-25 platform windows port published 2019-04-25 reporter Exploit-DB source https://www.exploit-db.com/download/46756 title RARLAB WinRAR 5.61 - ACE Format Input Validation Remote Code Execution (Metasploit) type local
Metasploit
| description | In WinRAR versions prior to and including 5.61, there is path traversal vulnerability when crafting the filename field of the ACE format (in UNACEV2.dll). When the filename field is manipulated with specific patterns, the destination (extraction) folder is ignored, thus treating the filename as an absolute path. This module will attempt to extract a payload to the startup folder of the current user. It is limited such that we can only go back one folder. Therefore, for this exploit to work properly, the user must extract the supplied RAR file from one folder within the user profile folder (e.g. Desktop or Downloads). User restart is required to gain a shell. |
| id | MSF:EXPLOIT/WINDOWS/FILEFORMAT/WINRAR_ACE |
| last seen | 2020-06-11 |
| modified | 2019-04-24 |
| published | 2019-04-15 |
| references | |
| reporter | Rapid7 |
| source | https://github.com/rapid7/metasploit-framework/blob/master//modules/exploits/windows/fileformat/winrar_ace.rb |
| title | RARLAB WinRAR ACE Format Input Validation Remote Code Execution |
Nessus
| NASL family | Windows |
| NASL id | WINRAR_5_70_BETA_1.NASL |
| description | The version of RARLAB WinRAR installed on the remote Windows host is prior to 5.70 Beta 1. It is, therefore, affected by the following vulnerabilities : - An error exists in the file |
| last seen | 2020-06-01 |
| modified | 2020-06-02 |
| plugin id | 122448 |
| published | 2019-02-27 |
| reporter | This script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof. |
| source | https://www.tenable.com/plugins/nessus/122448 |
| title | RARLAB WinRAR < 5.70 Beta 1 Multiple Vulnerabilities |
| code | |
Packetstorm
| data source | https://packetstormsecurity.com/files/download/152618/winrar_ace.rb.txt |
| id | PACKETSTORM:152618 |
| last seen | 2019-04-24 |
| published | 2019-04-24 |
| reporter | Imran Dawoodjee |
| source | https://packetstormsecurity.com/files/152618/RARLAB-WinRAR-ACE-Format-Input-Validation-Remote-Code-Execution.html |
| title | RARLAB WinRAR ACE Format Input Validation Remote Code Execution |
The Hacker News
id THN:A07AB56823D4BFBE5169047B76EE46F3 last seen 2019-03-15 modified 2019-03-15 published 2019-03-15 reporter The Hacker News source https://thehackernews.com/2019/03/winrar-hacking-malware.html title Patched WinRAR Bug Still Under Active Attack—Thanks to No Auto-Updates id THN:02CFB70636074934A6967135D3A69676 last seen 2019-03-28 modified 2019-03-28 published 2019-03-28 reporter The Hacker News source https://thehackernews.com/2019/03/apt33-cyber-espionage-hacking.html title Elfin Hacking Group Targets Multiple U.S. and Saudi Arabian Firms id THN:06853145247DE3A0858240BE3299325B last seen 2019-02-26 modified 2019-02-26 published 2019-02-26 reporter The Hacker News source https://thehackernews.com/2019/02/winrar-hacking-exploit.html title Latest WinRAR Flaw Being Exploited in the Wild to Hack Windows Computers
Related news
References
- https://www.win-rar.com/whatsnew.html
- http://www.securityfocus.com/bid/106948
- https://research.checkpoint.com/extracting-code-execution-from-winrar/
- https://github.com/blau72/CVE-2018-20250-WinRAR-ACE
- https://www.exploit-db.com/exploits/46552/
- http://packetstormsecurity.com/files/152618/RARLAB-WinRAR-ACE-Format-Input-Validation-Remote-Code-Execution.html
- http://www.rapid7.com/db/modules/exploit/windows/fileformat/winrar_ace
- https://www.exploit-db.com/exploits/46756/