Privilege escalation via oversized crontab step values
Published Aug 20, 2024 · Updated Aug 26, 2024
Heap-based buffer underflow in Vixie Cron before 9cc8ab1 and OpenBSD 7.4 and 7.5 allows local users to corrupt process memory. In entry.c, get_number converts an oversized positive step with atoi into a negative integer, and set_range passes the resulting index to bit_set outside its heap bitstring. On 64-bit builds, a crafted crontab step can crash cron or crontab and provides a blind out-of-bounds bit-write primitive for privilege escalation.
Summary
What happened
Heap-based buffer underflow in Vixie Cron before 9cc8ab1 and OpenBSD 7.4 and 7.5 allows local users to corrupt process memory. In entry.c, get_number converts an oversized positive step with atoi into a negative integer, and set_range passes the resulting index to bit_set outside its heap bitstring. On 64-bit builds, a crafted crontab step can crash cron or crontab and provides a blind out-of-bounds bit-write primitive for privilege escalation.
The record
- CVE
- CVE-2024-43688
- Published
- Aug 20, 2024
- Updated
- Aug 26, 2024
- Vendor
- OpenBSD Project
- Product
- OpenBSD
- Classifications
- CWE-787, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Aug 20, 2024CVE publishedPublication date reported by the CVE source.
- Aug 26, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=7.4
- Affected versionversion=7.5
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
- Oversized crontab step heap-underflow triggerproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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