Out-of-Bounds

Affecting wget package, versions <1.18-5+deb9u1

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Overview

The retr.c:fd_read_body() function is called when processing OK responses. 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 read the chunk in pieces of 8192 bytes by using the MIN() macro, but ends up passing the negative chunk length to retr.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. The attacker can corrupt malloc metadata after the allocated buffer.

References

CVSS Score

8.8
high severity
  • Attack Vector
    Network
  • Attack Complexity
    Low
  • Privileges Required
    None
  • User Interaction
    Required
  • Scope
    Unchanged
  • Confidentiality
    High
  • Integrity
    High
  • Availability
    High
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVE
CVE-2017-13090
CWE
CWE-119 CWE-122
Snyk ID
SNYK-DEBIAN9-WGET-300444
Disclosed
27 Oct, 2017
Published
27 Oct, 2017