Signature Detail

HTTP: LibPNG Transparency Chunk Length Buffer Overflow

This signature detects attempts to exploit a known vulnerability in the way libpng handles the transparency chunk of a PNG image. A successful attack could allow the attacker to execute arbitrary code on the targeted system. Failed exploit attempts could result in a denial of service condition.

Extended Description

Multiple buffer overflows in libpng 1.2.5 and earlier, as used in multiple products, allow remote attackers to execute arbitrary code via malformed PNG images in which (1) the png_handle_tRNS function does not properly validate the length of transparency chunk (tRNS) data, or the (2) png_handle_sBIT or (3) png_handle_hIST functions do not perform sufficient bounds checking.

Affected Products

• Greg_roelofs libpng up to 1.2.5
• Microsoft msn_messenger 6.1
• Microsoft msn_messenger 6.2
• Microsoft windows_98se
• Microsoft windows_me (:second_edition)
• Microsoft windows_media_player 9
• Microsoft windows_messenger 5.0

References

• BugTraq: 10857
• CVE: CVE-2004-0597
• URL: http://www.kb.cert.org/vuls/id/388984