Arbitrary File Write via Archive Extraction (Zip Slip) Affecting github.com/artdarek/go-unzip package, versions <1.0.0
Threat Intelligence
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Test your applications- Snyk IDSNYK-GOLANG-GITHUBCOMARTDAREKGOUNZIP-559505
- published5 Mar 2020
- disclosed5 Mar 2020
- creditSam Sanoop of Snyk Security Team
Introduced: 5 Mar 2020
CVE NOT AVAILABLE CWE-29 (opens in a new tab)How to fix?
Upgrade github.com/artdarek/go-unzip to version 1.0.0 or higher.
Overview
github.com/artdarek/go-unzip is a package go-unzip provides a very simple library to extract zip archive
Affected versions of this package are vulnerable to Arbitrary File Write via Archive Extraction (Zip Slip). ZIP Path traversal is possible during extraction due to no validation and sanitization of filenames.
PoC
package main import ("github.com/yi-ge/unzip" "fmt")
func main() { u := unzip.New("/home/snoopy/zip-slip.zip", "/home/snoopy/uploads") err := u.Extract() if err != nil { fmt.Println(err) } }
Details
It is exploited using a specially crafted zip archive, that holds path traversal filenames. When exploited, a filename in a malicious archive is concatenated to the target extraction directory, which results in the final path ending up outside of the target folder. For instance, a zip may hold a file with a "../../file.exe" location and thus break out of the target folder. If an executable or a configuration file is overwritten with a file containing malicious code, the problem can turn into an arbitrary code execution issue quite easily.
The following is an example of a zip archive with one benign file and one malicious file. Extracting the malicous file will result in traversing out of the target folder, ending up in /root/.ssh/ overwriting the authorized_keys file:
+2018-04-15 22:04:29 ..... 19 19 good.txt
+2018-04-15 22:04:42 ..... 20 20 ../../../../../../root/.ssh/authorized_keys