7-Zip and p7zip NCompress::NShrink::CDecoder::CodeReal Vulnerability [CVE-2017-17969]

CVE Number – CVE-2017-17969

A vulnerability in 7-Zip and p7zip could allow an unauthenticated, remote attacker to execute arbitrary code or cause a denial of service (DoS) condition on a targeted system.The vulnerability is due to a heap-based buffer overflow condition in the NCompress::NShrink::CDecoder::CodeReal method of the affected software. An attacker could exploit this vulnerability by sending a crafted ZIP archive file that submits malicious input to a targeted system. A successful exploit could trigger an out-of-bounds write condition that the attacker could use to execute arbitrary code or cause a DoS condition.Proof-of-concept (PoC) code that demonstrates an exploit of this vulnerability is publicly available.7-Zip has confirmed the vulnerability and released software updates.

Analysis

• To exploit this vulnerability, an attacker must send a crafted ZIP archive file that submits malicious input to the targeted system, making exploitation more difficult in environments that restrict network access from untrusted sources.

Safeguards

• Administrators are advised to apply the appropriate updates.Administrators are advised to allow only trusted users to have network access.Administrators are advised to run both firewall and antivirus applications to minimize the potential of inbound and outbound threats.Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.Administrators can help protect affected systems from external attacks by using a solid firewall strategy.Administrators are advised to monitor affected systems.

Vendor Announcements

• 7-Zip has released a changelog at the following link: 18.00 – 2018-01-10

Fixed Software

• 7-Zip has released software updates at the following link: 7-Zip 18.00 or later