semver is a semantic version parser used by npm.
-Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) via the function new Range, when untrusted user data is provided as a range.
- const semver = require('semver')
- const lengths_2 = [2000, 4000, 8000, 16000, 32000, 64000, 128000]
-
- console.log("n[+] Valid range - Test payloads")
- for (let i = 0; i =1.2.3' + ' '.repeat(lengths_2[i]) + '<1.3.0';
- const start = Date.now()
- semver.validRange(value)
- // semver.minVersion(value)
- // semver.maxSatisfying(["1.2.3"], value)
- // semver.minSatisfying(["1.2.3"], value)
- // new semver.Range(value, {})
-
- const end = Date.now();
- console.log('length=%d, time=%d ms', value.length, end - start);
- }
- Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.
-The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.
-Let’s take the following regular expression as an example:
-regex = /A(B|C+)+D/
- This regular expression accomplishes the following:
-A The string must start with the letter 'A'(B|C+)+ The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the + matches one or more times). The + at the end of this section states that we can look for one or more matches of this section.D Finally, we ensure this section of the string ends with a 'D'The expression would match inputs such as ABBD, ABCCCCD, ABCBCCCD and ACCCCCD
It most cases, it doesn't take very long for a regex engine to find a match:
-$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
- 0.04s user 0.01s system 95% cpu 0.052 total
-
- $ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
- 1.79s user 0.02s system 99% cpu 1.812 total
- The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.
-Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.
-Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:
-The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.
-From there, the number of steps the engine must use to validate a string just continues to grow.
-| String | -Number of C's | -Number of steps | -
|---|---|---|
| ACCCX | -3 | -38 | -
| ACCCCX | -4 | -71 | -
| ACCCCCX | -5 | -136 | -
| ACCCCCCCCCCCCCCX | -14 | -65,553 | -
By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.
-Upgrade semver to version 7.5.2 or higher.
Note: Versions mentioned in the description apply only to the upstream openssl package and not the openssl package as distributed by Alpine:3.18.
+ See How to fix? for Alpine:3.18 relevant fixed versions and status.
Issue summary: The AES-SIV cipher implementation contains a bug that causes + it to ignore empty associated data entries which are unauthenticated as + a consequence.
+Impact summary: Applications that use the AES-SIV algorithm and want to + authenticate empty data entries as associated data can be mislead by removing + adding or reordering such empty entries as these are ignored by the OpenSSL + implementation. We are currently unaware of any such applications.
+The AES-SIV algorithm allows for authentication of multiple associated + data entries along with the encryption. To authenticate empty data the + application has to call EVP_EncryptUpdate() (or EVP_CipherUpdate()) with + NULL pointer as the output buffer and 0 as the input buffer length. + The AES-SIV implementation in OpenSSL just returns success for such a call + instead of performing the associated data authentication operation. + The empty data thus will not be authenticated.
+As this issue does not affect non-empty associated data authentication and + we expect it to be rare for an application to use empty associated data + entries this is qualified as Low severity issue.
+Upgrade Alpine:3.18 openssl to version 3.1.1-r2 or higher.
Note: Versions mentioned in the description apply only to the upstream openssl package and not the openssl package as distributed by Alpine:3.18.
+ See How to fix? for Alpine:3.18 relevant fixed versions and status.
Issue summary: Checking excessively long DH keys or parameters may be very slow.
+Impact summary: Applications that use the functions DH_check(), DH_check_ex() + or EVP_PKEY_param_check() to check a DH key or DH parameters may experience long + delays. Where the key or parameters that are being checked have been obtained + from an untrusted source this may lead to a Denial of Service.
+The function DH_check() performs various checks on DH parameters. One of those + checks confirms that the modulus ('p' parameter) is not too large. Trying to use + a very large modulus is slow and OpenSSL will not normally use a modulus which + is over 10,000 bits in length.
+However the DH_check() function checks numerous aspects of the key or parameters + that have been supplied. Some of those checks use the supplied modulus value + even if it has already been found to be too large.
+An application that calls DH_check() and supplies a key or parameters obtained + from an untrusted source could be vulernable to a Denial of Service attack.
+The function DH_check() is itself called by a number of other OpenSSL functions. + An application calling any of those other functions may similarly be affected. + The other functions affected by this are DH_check_ex() and + EVP_PKEY_param_check().
+Also vulnerable are the OpenSSL dhparam and pkeyparam command line applications + when using the '-check' option.
+The OpenSSL SSL/TLS implementation is not affected by this issue. + The OpenSSL 3.0 and 3.1 FIPS providers are not affected by this issue.
+Upgrade Alpine:3.18 openssl to version 3.1.1-r3 or higher.