Editing ACE (compressed file format)

{{about|the data compression format|the file format specification used in genomics|ACE (genomic file format)}}

{{one source|date=February 2016}}
{{Infobox file format
| name = ACE
| extension = .ace
| mime = application/x-ace-compressed
| owner = e-merge GmbH
| released = {{start date and age|1999|7|22}}
| creatorcode =
| genre = [[data compression]]
| containerfor =
| containedby =
| extendedfrom =
| extendedto =
}}
In [[computing]], '''ACE''' is a proprietary [[data compression]] archive [[file format]] developed by Marcel Lemke, and later bought by e-merge GmbH. The peak of its popularity was 1999–2001, when it provided slightly better compression rates than [[RAR (file format)|RAR]], which has since become more popular.

==WinAce==
{{Main|WinAce}}
[[WinAce]], maintained by e-merge GmbH, is used to compress and decompress ACE files under [[Microsoft Windows]]. When installed, it lets the user choose between paying for a registration or installing [[WhenU SaveNow]] [[adware]]. e-merge GmbH also produces a [[WinAce#Commandline version|Commandline ACE]] for DOS; and a freeware [[command-line interface]] decompression tool for [[Linux]] ([[Intel 80386|i386]]) and [[macOS]] called "Unace". e-merge GmbH also provides several libraries for developers, including a freeware decompression [[dynamic-link library|DLL]] called "unace.dll". Some third-party archivers can read the format using this DLL. None of the above is [[open-source model|open source]] [[free software]].

On November 23, 2007, version 2.69 of WinACE was released, including a less-intrusive [[adware]] application, MeMedia AdVantage, which replaces WhenU. No other major changes are in this release.

==Other implementations==
An older version of an Unace 1.2b is [[free software]] and licensed under the [[GNU General Public License|GPL]] by the author Marcel Lemke, but it cannot extract ACE archives from version 2.0 and newer.<ref>{{cite web|url=https://packages.debian.org/stable/utils/unace|title=unace: extract, test and view .ace archives|website=Debian}}</ref>

A newer version of Unace 2.5 that supports ACE 2.0 archives is available under a restrictive [[source available]] license, also by Marcel Lemke.<ref>{{cite web|url=https://packages.debian.org/stable/utils/unace-nonfree|title=unace-nonfree: extract, test and view .ace archives (non-free version)|website=Debian}}</ref>

An older, independent [[C_(programming_language)|C]] implementation is part of [[XAD_(software)|XAD-Master libxad]] by Dirk Stöcker. It is limited to unpacking ACE 1.0 archives.

Since 2017, there is a [[BSD licenses|BSD licensed]] [[Python_(programming_language)|python]] module and [[Command-line_interface|CLI]] utility by Daniel Roethlisberger, that supports unpacking of ACE 2.0 format archives.<ref>{{cite web|url=https://pypi.python.org/pypi/acefile|title=acefile: Read/test/extract ACE 1.0 and 2.0 archives in pure python|website=PyPI|access-date=2019-03-09}}</ref>

==Third-party support==
''Packing'' of ACE files is licensed as proprietary information and only available through WinACE, while ''unpacking'' of ACE files is supported by a number of [[comparison of file archivers#Archive format support|third-party archivers]]. However, virtually all of them (the ones that support ACE 2.x format) do this by using the proprietary "unace.dll" from e-merge GmbH.

==Use for malware distribution==
Since at least 2015, ACE archives have been used to deliver [[malware]] to victims by e-mail. This tactic was viable because popular [[File_archiver|archiving software]] was able to uncompress ACE archives, but support for the ACE format in security products such as [[Email_filtering|mail filters]], [[Content-control_software|web content filters]], and [[Antivirus_software|anti-virus software]] was generally weak.<ref>{{cite web|url=http://blog.frankleonhardt.com/2015/malware-sent-in-ace-format/|title=Malware sent in .ace format|website=Frank Leonhardt's blog|date=5 October 2015 |access-date=2019-03-09}}</ref><ref>{{cite web|url=https://exchange.xforce.ibmcloud.com/collection/Spammers-discover-the-7z-archive-format-for-spreading-ransomware-1b8e1aad140a017769c7eba02f500747|title=Spammers discover the 7z archive format for spreading ransomware|website=IBM X-Force Exchange|access-date=2019-03-09}}</ref><ref>{{cite web|url=https://medium.com/@seifreed/how-to-deal-with-ace-malware-files-592eb52e7135|archive-url=https://archive.today/20191024094243/https://medium.com/@seifreed/how-to-deal-with-ace-malware-files-592eb52e7135|url-status=dead|archive-date=October 24, 2019|title=How to deal with .ACE malware files?|website=Marc Rivero López' blog|date=24 January 2017|access-date=2019-03-09}}</ref>

==Security vulnerabilities==
In February 2019 several major security vulnerabilities were found in the unacev2.dll library which is used by [[WinRAR]] and other archiving products. Since WinACE support is discontinued, users are advised against opening ACE archives in WinRAR and possibly other products using this library.<ref>{{cite web|url=https://research.checkpoint.com/extracting-code-execution-from-winrar/|title=Extracting a 19 Year Old Code Execution from WinRAR|date=2019-02-20|website=Check Point Research|language=en-US|access-date=2019-02-26}}</ref> WinRAR stopped supporting ACE as of version 5.70, and similar products are following suit.

==See also==
*[[Comparison of archive formats]]
*[[Comparison of file archivers]]
*[[List of archive formats]]

==References==
{{Reflist}}

==External links==
* [https://web.archive.org/web/20170714193504/http://winace.com/ Official Website - Web Archive Snapshot from 14.07.2017] {{in lang|en}}
* [https://web.archive.org/web/20110121225116/http://www.winace.net/files/wace269i.exe Download link for last Version 2.69i - Web Archive Snapshot from 21.01.2011]


{{Archive formats}}
{{DEFAULTSORT:Ace (File Format)}}

[[Category:Archive formats]]