Vba32 Antivirus v3.36.0 - DoS

Description

Vba32 Antivirus v3.36.0 is vulnerable to a Denial of Service vulnerability by triggering the 0x2220A7 IOCTL code of the Vba32m64.sys driver.

Vulnerability

The 0x2220A7 IOCTL code of the Vba32m64.sys driver is vulnerable to DoS, leading to a BSOD of the affected computer caused by a NULL pointer dereference. If an attacker sends an nOutBufferSize parameter greater or equal than 0x2E, the execution flow will reach the function sub_11B34 which doesn't verify the return address of another routine:

v2 = sub_128A8((__int64)&qword_1D710);
v3 = v2; // [1]
if ( v2 )
{
    v4 = sub_12750(v2);
}
else
{
    v5 = sub_128A8((__int64)&qword_1D600);
    v3 = v5;
    if ( !v5 )
        return 0;
    v4 = sub_1278C(v5, 2i64);
    *(_QWORD *)(v3 + 0x50) = MEMORY[0xFFFFF78000000014] + 0x2FAF080i64;
    sub_12830(&qword_1D650, v3);
}
v6 = (_WORD *)(a1 + 0x2C);
*(_QWORD *)(a1 + 0x10) = *(_QWORD *)(v3 + 0x40); // [2]

At [1], the return value is assigned to a variable which is then dereferenced at [2] without checking for its value, leading to a NULL pointer dereference:

rax=0000000000000000 rbx=0000000000000000 rcx=0000000000000001
rdx=0000000000000001 rsi=00000000031ac0f4 rdi=00000000031ac120
rip=fffff80447e41b6e rsp=ffffc9816c7fc730 rbp=0000000000000000
 r8=00000000ffffffff  r9=7ffff80447e4d6b0 r10=7ffffffffffffffc
r11=0000000000000000 r12=0000000000000020 r13=0000000000000030
r14=ffffe20fa72678b0 r15=ffffe20fa0e9b060
iopl=0         nv up ei pl zr na po nc
cs=0010  ss=0018  ds=002b  es=002b  fs=0053  gs=002b             efl=00050246
Vba32m64+0x1b6e:
fffff804`47e41b6e 488b4340        mov     rax,qword ptr [rbx+40h] ds:002b:00000000`00000040

Our security policy

We have reserved the ID CVE-2024-23441 to refer to this issue from now on.

Disclosure policy

System Information

• Version: Vba32 Antivirus v3.36.0

• Operating System: Windows

Mitigation

There is currently no patch available for this vulnerability.

References

• Vendor page https://www.anti-virus.by/

• Product page https://www.anti-virus.by/vba32