-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 National Cyber Alert System Technical Cyber Security Alert TA10-279A Adobe Reader and Acrobat Affected by Multiple Vulnerabilities Original release date: October 06, 2010 Last revised: -- Source: US-CERT Systems Affected * Adobe Reader 9.3.4 and earlier versions for Windows, Macintosh, and UNIX * Adobe Acrobat 9.3.4 and earlier versions for Windows and Macintosh * Adobe Reader 8.2.4 and earlier versions for Windows, Macintosh, and UNIX * Adobe Acrobat 8.2.4 and earlier versions for Windows and Macintosh Overview Adobe has released Security Bulletin APSB10-21, which describes multiple vulnerabilities affecting Adobe Reader and Acrobat. I. Description Adobe Security Bulletin APSB10-21 describes a number of vulnerabilities affecting Adobe Reader and Acrobat. These vulnerabilities affect Reader and Acrobat 9.3.4, earlier 9.x versions, 8.2.4, and earlier 8.x versions. An attacker could exploit these vulnerabilities by convincing a user to open a specially crafted PDF file. The Adobe Reader browser plug-in, which can automatically open PDF documents hosted on a website, is available for multiple web browsers and operating systems. Additional information is available in US-CERT Vulnerability Note VU#491991. II. Impact These vulnerabilities could allow a remote attacker to execute arbitrary code, write arbitrary files or folders to the file system, escalate local privileges, or cause a denial of service on an affected system as the result of a user opening a malicious PDF file. III. Solution Update Adobe has released updates to address this issue. Users are encouraged to read Adobe Security Bulletin APSB10-21 and update vulnerable versions of Adobe Reader and Acrobat. Disable JavaScript in Adobe Reader and Acrobat Disabling JavaScript may prevent some exploits from resulting in code execution. Acrobat JavaScript can be disabled using the Preferences menu (Edit -> Preferences -> JavaScript; uncheck Enable Acrobat JavaScript). Adobe provides a framework to blacklist specific JavaScipt APIs. If JavaScript must be enabled, this feature may be useful when specific APIs are known to be vulnerable or used in attacks. Prevent Internet Explorer from automatically opening PDF files The installer for Adobe Reader and Acrobat configures Internet Explorer to automatically open PDF files without any user interaction. This behavior can be reverted to a safer option that prompts the user by importing the following as a .REG file: Windows Registry Editor Version 5.00 [HKEY_CLASSES_ROOT\AcroExch.Document.7] "EditFlags"=hex:00,00,00,00 Disable the display of PDF files in the web browser Preventing PDF files from opening inside a web browser will partially mitigate this vulnerability. If this workaround is applied, it may also mitigate future vulnerabilities. To prevent PDF files from automatically being opened in a web browser, do the following: 1. Open Adobe Acrobat Reader. 2. Open the Edit menu. 3. Choose the Preferences option. 4. Choose the Internet section. 5. Uncheck the "Display PDF in browser" checkbox. Do not access PDF files from untrusted sources Do not open unfamiliar or unexpected PDF files, particularly those hosted on websites or delivered as email attachments. Please see Cyber Security Tip ST04-010. IV. References * Security update available for Adobe Reader and Acrobat - * US-CERT Vulnerability Note VU#491991 - * Adobe Reader and Acrobat JavaScript Blacklist Framework - ____________________________________________________________________ The most recent version of this document can be found at: ____________________________________________________________________ Feedback can be directed to US-CERT Technical Staff. Please send email to with "TA10-279A Feedback VU#491991" in the subject. ____________________________________________________________________ For instructions on subscribing to or unsubscribing from this mailing list, visit . ____________________________________________________________________ Produced 2010 by US-CERT, a government organization. Terms of use: ____________________________________________________________________ Revision History October 06, 2010: Initial release -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.5 (GNU/Linux) iQEVAwUBTKxxvD6pPKYJORa3AQIL3wgAp2tynQw73VA+B70fuEl+os17BeVaP8zn 5aoWS6QBRx+Q8Ijw1wnKT1sF4IWaDWTWqPo0yt6MLx8WwO2ei8WaB+aMOwy9ZBo3 BbCOPSM63/3jBrJuCDs4x2PhZDzg2GJf4Zw8NN2oCSOXMxYGhx16QQzo2lY35CBJ cvCSiLtNQuqpnvNMi2DJhArwxStK9Un2fli7IqwXzC6+RIgrk1l/EAM/6CO2+AwJ Se0bDWBjwR5YverLEXoLuBbF0lHvQ0+V/vT5Q/zBDYUwcWkBL2n7NwdbKI9pYZxL 8Te7YapqAnMNgI1/PnYI/W369Vq3U6QoQVVR9ZoyLGw8x0A57cpU2g== =Rc0h -----END PGP SIGNATURE-----