hashcat's fgetl() function in src/filehandling.c writes a null terminator one byte past the caller's buffer when an input line is exactly the buffer length. Attackers can trigger this out-of-bounds heap write by providing a hash file, potfile, or wordlist containing a line of exactly HCBUFSIZ_LARGE bytes.
Attack Parameters
Attack Vector
Local
Requires local access
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
Passive
Minimal interaction
Impact Assessment
Confidentiality
None
No data leak
Integrity
Low
Partial data modification
Availability
High
Complete denial of service
CVSS Vector v4.0
Weakness Type (CWE)
References 5
https://github.com/hashcat/hashcat
disclosure@vulncheck.com
https://github.com/hashcat/hashcat/blob/v7.1.2/src/filehandling.c#L1032-L1060
disclosure@vulncheck.com
https://github.com/hashcat/hashcat/commit/93b55d37d3b2340013d4036f10181ddc67d44…
disclosure@vulncheck.com
https://github.com/hashcat/hashcat/issues/4739
disclosure@vulncheck.com
https://www.vulncheck.com/advisories/hashcat-through-off-by-one-out-of-bounds-h…
disclosure@vulncheck.com