cbcvebase.
CVE-2003-0161
published 2003-04-02

CVE-2003-0161: The prescan() function in the address parser (parseaddr.c) in Sendmail before 8.12.9 does not properly handle certain conversions from char and int types…

PriorityP347critical10CVSS 2.0
AVNACLAuNCCICAC
EXPLOIT
EPSS
38.19%
98.4th percentile
The prescan() function in the address parser (parseaddr.c) in Sendmail before 8.12.9 does not properly handle certain conversions from char and int types, which can cause a length check to be disabled when Sendmail misinterprets an input value as a special "NOCHAR" control value, allowing attackers to cause a denial of service and possibly execute arbitrary code via a buffer overflow attack using messages, a different vulnerability than CVE-2002-1337.

Affected

107 ranges· showing 25
VendorProductVersion rangeFixed in
compaqtru64
compaqtru64
compaqtru64
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compaqtru64
compaqtru64
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compaqtru64
compaqtru64
compaqtru64
compaqtru64
compaqtru64
compaqtru64
compaqtru64
compaqtru64
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compaqtru64

Detection & IOCsextracted from sources · hover to see the quote

commandRCPT TO: <...overflow payload...>
path/usr/sbin/sendmail
path/usr/sbin/sendmail.sendmail
snort
alert tcp $EXTERNAL_NET any -> $SMTP_SERVERS 25 (msg:"GPL SMTP EXPN overflow attempt"; flow:established,to_server; content:"EXPN"; nocase; isdataat:255,relative; content:!"|0a|"; within:255; pcre:"/^EXPN[^\n]{255}/smi"; reference:bugtraq,6991; reference:bugtraq,7230; reference:cve,2002-1337; reference:cve,2003-0161; classtype:attempted-admin; sid:2102259; rev:10; metadata:created_at 2010_09_23, cve CVE_2002_1337, confidence Medium, signature_severity Major, updated_at 2024_03_08;)
  • Detect SMTP sessions where RCPT TO or EXPN headers exceed 255 bytes without a newline — indicative of prescan() overflow attempt
  • The exploit embeds 0xff bytes in SMTP address fields to cause Sendmail to misinterpret the value as the special NOCHAR control value, disabling the length check
  • Crash signature for successful PoC exploitation: SIGSEGV at address 0x5c5c5c5c — monitor for sendmail process crashes with this instruction pointer value
  • Characters that cannot be passed through the vulnerable prescan() path (useful for payload filtering/allowlisting): 0x00, 0xff, 0x09-0x0d, 0x20-0x22, 0x25, 0x28, 0x29, 0x2b, 0x2c, 0x2e, 0x2f, 0x3a-0x3c, 0x3e, 0x40, 0x5b, 0x5d, 0x5e, 0x80-0x9f
  • ·The vulnerability affects Sendmail versions before 8.12.9; the fix was introduced in 8.12.9. Ensure the installed version is 8.12.9 or later.
  • ·The Snort rule (sid:2102259) references both CVE-2002-1337 and CVE-2003-0161 and fires on EXPN overflow patterns; operators should ensure this rule is enabled on SMTP inspection paths and not suppressed.

CVSS provenance

nvdv2.010.0CRITICALAV:N/AC:L/Au:N/C:C/I:C/A:C
osv10.0CRITICAL
vendor_debian10.0CRITICAL
vendor_redhat10.0CRITICAL
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