HTTP: GNU Wget skip_short_body Stack Buffer Overflow

This signature detects attempts to exploit a known vulnerability against GNU wget. A successful attack can lead to a buffer overflow and arbitrary remote code execution within the context of the client.

Extended Description

The http.c:skip_short_body() function is called in some circumstances, such as when processing redirects. When the response is sent chunked in wget before 1.19.2, the chunk parser uses strtol() to read each chunk's length, but doesn't check that the chunk length is a non-negative number. The code then tries to skip the chunk in pieces of 512 bytes by using the MIN() macro, but ends up passing the negative chunk length to connect.c:fd_read(). As fd_read() takes an int argument, the high 32 bits of the chunk length are discarded, leaving fd_read() with a completely attacker controlled length argument.

Affected Products

Debian debian_linux

References

BugTraq: 101592 101590

CVE: CVE-2017-13090

URL: https://www.viestintavirasto.fi/en/cybersecurity/vulnerabilities/2017/haavoittuvuus-2017-037.html http://git.savannah.gnu.org/cgit/wget.git/commit/?h=v1.19.2&id=ba6b44f6745b14dce414761a8e4b35d31b176bba

Short Name

HTTP:STC:GNU-WGET-NEG-CHUNK-BO

Severity

Critical

Recommended

False

Recommended Action

Drop

HTTP: GNU Wget skip_short_body Stack Buffer Overflow

Extended Description

Affected Products

References

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