cbcvebase.
CVE-1999-0920
published 1999-05-26

CVE-1999-0920: Buffer overflow in the pop-2d POP daemon in the IMAP package allows remote attackers to gain privileges via the FOLD command.

PriorityP347critical10CVSS 2.0
AVNACLAuNCCICAC
EXPLOIT
EPSS
32.37%
98.1th percentile
Buffer overflow in the pop-2d POP daemon in the IMAP package allows remote attackers to gain privileges via the FOLD command.

Affected

1 ranges
VendorProductVersion rangeFixed in
university_of_washingtonimap

Detection & IOCsextracted from sources · hover to see the quote

commandFOLD <~1000 byte argument>
commandHELO %s:%s %s
commandFOLD %s
port109
bytes
\xeb\x1f\x5e\x89\x76\x08\x31\xc0\x88\x46\x07\x89\x46\x0c\xb0\x0b\x89\xf3\x8d\x4e\x08\x8d\x56\x0c\xcd\x80\x31\xdb\x89\xd8\x40\xcd\x80\xe8\xdc\xff\xff\xff/bin/sh
  • Alert on POP2 (TCP/109) FOLD commands with arguments exceeding ~986–1000 bytes, indicative of stack-based buffer overflow exploitation against ipop2d.
  • Monitor for the exploit's HELO sequence followed immediately by an oversized FOLD command on TCP/109 — the exploit sends HELO with host:user pass then FOLD with ~986-byte NOP-sled/shellcode buffer.
  • Scan network traffic on TCP/109 for the Linux x86 shellcode byte sequence \xeb\x1f\x5e\x89\x76\x08\x31\xc0 associated with this exploit's execve(/bin/sh) payload.
  • The Metasploit auxiliary module exploits the same FOLD command for arbitrary file retrieval; detect authenticated POP2 sessions issuing FOLD with path-like arguments (e.g., containing '/' characters) to retrieve world/group-readable files.
  • ·The file retrieval variant (Metasploit module) requires a valid username and password for the POP account; it cannot be exploited anonymously.
  • ·The stack return address used in the exploit (0xbffff3c0) is Linux x86-specific and may require offset tuning; the exploit accepts an offset argument to adjust.
  • ·Successful exploitation only yields 'nobody' user privileges, not root, due to the anonymous_login() uid drop in ipop2d.
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