NULL Pointer Dereference Affecting heimdal package, versions <7.4.0-r2
Threat Intelligence
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-ALPINE310-HEIMDAL-454861
- published6 Dec 2017
- disclosed6 Dec 2017
Introduced: 6 Dec 2017
CVE-2017-17439 (opens in a new tab)How to fix?
Upgrade Alpine:3.10 heimdal to version 7.4.0-r2 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream heimdal package and not the heimdal package as distributed by Alpine.
See How to fix? for Alpine:3.10 relevant fixed versions and status.
In Heimdal through 7.4, remote unauthenticated attackers are able to crash the KDC by sending a crafted UDP packet containing empty data fields for client name or realm. The parser would unconditionally dereference NULL pointers in that case, leading to a segmentation fault. This is related to the _kdc_as_rep function in kdc/kerberos5.c and the der_length_visible_string function in lib/asn1/der_length.c.
References
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-17439
- https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=878144
- https://www.debian.org/security/2017/dsa-4055
- https://security-tracker.debian.org/tracker/CVE-2017-17439
- https://github.com/heimdal/heimdal/commit/1a6a6e462dc2ac6111f9e02c6852ddec4849b887
- https://github.com/heimdal/heimdal/issues/353
- http://h5l.org/advisories.html?show=2017-12-08
- http://www.h5l.org/pipermail/heimdal-announce/2017-December/000008.html
- http://www.h5l.org/pipermail/heimdal-discuss/2017-August/000259.html