InfoSecBulletin Cybersecurity for mankind
CISA has issued a warning about a vulnerability in unencrypted persistent cookies in the F5 BIG-IP Local Traffic Manager (LTM) module. This issue poses a risk for organizations using F5 BIG-IP, as it can be exploited by cybercriminals.
CISA warns that cybercriminals are using unencrypted persistent cookies to discover details about non-internet- facing devices on networks. This information can help them find and exploit vulnerabilities in other systems, increasing risks for organizations as attackers can gain broader access across the network.
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The F5 BIG-IP LTM module uses persistent cookies for session continuity but can be vulnerable if these cookies are unencrypted. Attackers can exploit this to gather network information. F5 states that enabling cookie encryption uses a 192-bit AES cipher followed by Base64 encoding, which is crucial for protecting cookies from unauthorized access.
Without encryption, these cookies allow attackers to access the internal network structure, revealing details about other devices and their setups. This information can help them exploit vulnerabilities in the network.
CISA recommends that organizations using F5 BIG-IP devices encrypt their persistent cookies to mitigate risks. They also advise reviewing F5’s guidelines for properly configuring the BIG-IP LTM system for encrypted HTTP cookies. Additionally, F5 offers iHealth, a tool that alerts users when cookie encryption is disabled.
F5 BIG-IP solutions are widely used in various industries, including finance and healthcare. The vulnerability of unencrypted cookies poses risks like session hijacking and allows attackers to explore the network. Encrypting these persistent cookies can help organizations lessen their attack surface and safeguard their internal network from cyber threats.
